text:
When to choose Lantids and how to make the most from them
I love Gaia Project. But there are some races I havn't quite "cracked" yet. So I figured I would try to start a thread here for each race.
I will then provide a response with the do's and don'ts that I've figured out so far.
Some things are always relevant before you choose a race. Such as the amount and layout of the planets. The more planets of the right colour, the better. Even more so, if there are planets nearby, that only needs to be terraformed a single step to become habitable. And hopefully they are not all situated near the border of the map. You also want to start near other players. No need to address these points each and every time.
So: When to choose Lantids, and how to make the most from them?
Summary of the Lantids, for those who do not remember : Lantids has the ability to build mines on planets already colonized by other players. The Lantids won't have to pay anything for terraforming when doing so, but will not be able to upgrade these mines, and these planets will NOT count, when a check is made for number of Gaia planets colonized or the amount of different planet types colonized, as these planets were not originally colonized by the Lantids. When the Planetary Institute is built, the Lantids will get a bonus 2 tech every time they build a mine on a planet already colonized by another player.

Lantids will become more attractive to pick, the more of the following are true:

It will be easier to find suitable planets to colonize in games with high player count. So they will be more attractive in a four player game, than in games with fewer players.
During the first or second turn, you will get bonus points for building your Planetary Institute
The round booster giving points for each mine is in play. Lantids should on average have a high number of mines in play already midgame.

Lantids will become less attractive to pick, the more of the following are true:

One of the endgame bonuses is for number of colonized Gaia planets.
One of the endgame bonuses is for number of different planet types colonized.
It's a two- or three-player game.

During the game, you will probably want to:

Get your Planetary Institute on the board early, enabling your special ability to get tech every time you build a mine on another players planet.
Once your Planetary Institute is in play, you should spam mines. This will elevate your income of Iron, and net you a nice boost in tech.
Save one or two mines, though. And be very careful to only build these on planets that have neighbours. Thus you will be able to upgrade them to Trading Stations at the cheap rate, and get the mine back for colonizing new planets later on.

(My personal best score with Lantids at the time of writing this is a mere 148 points. So take my advices for what they are. I'm sure there's more to consider.)


text:
When to choose Terrans and how to make the most from them
I love Gaia Project. But there are some races I havn't quite "cracked" yet. So I figured I would try to start a thread here for each race. I will try with this one, and if people like it, I will follow up with each of the other races in turn.
I will start with one of the races I do think I've got a fair handle on.
I will then provide a response with the do's and don'ts that I've figured out so far.
Some things are always relevant before you choose a race. Such as the amount and layout of the planets. The more planets of the right colour, the better. Even more so, if there are planets nearby, that only needs to be terraformed a single step to become habitable. And hopefully they are not all situated near the border of the map. You also want to start near other players. No need to address these points each and every time.
So: When to choose Terrans, and how to make the most from them?
Summary of the Terrans, for those who do not remember :
Start one place up the Gaia tech track, making you start with one of the three terraformers activated.
Once the Planetary Institute has been built, every Gaia phase, you may obtain resources for the powerdiscs that are moved back into your power bowls. 4 discs for a QI cube. 3 discs for an Iron. 4 discs for a Tech. 1 disc for a Gold.

Terrans will become more attractive to pick, the more of the following are true:

You are able to pick starting positions, where you can use your terraformer. Ie. the purple planet is next to or close to a blue planet. Preferably both your starting planets.
During the first or second turn, you will get bonus points for building your Planetary Institute
During the game, you will get bonus points for colonizing Gaia planets.
The round booster giving points for colonized Gaia planets is available.

During the game, you will probably want to:

Get your Planetary Institute on the board early, enabling your special ability to obtain stuff for free during the Gaia phase.
Get hold of the tech tile, which allows you to take a special action giving you 4 power.
Use this tech tile in combination with your terraformer. Use the terraformer to move a bunch of power tokens from your 1-bowl into the Gaia bowl. In the next turn, these will return to your 2-bowl. And with the special action, your will quickly have 4 power pushed into your 3-bowl. Once they are spent, one of your last actions that turn, should be to use your terraformer, thereby emptying your 1-bowl. Clean-rinse-repeat.
If one of the late game turn bonuses is the 4-points for colonizing Gaia Planets, you may want to go deep in the Gaia tech track, enabling you to terraform three purple planets on the turn just before that, and then follow up with colonizing three Gaia planets and netting 12 points.
If it suits your plans, you may also want to pick up the tech tile, that gives you 3 points every time you colonize a Gaia planet. The earlier the better.

I think it would be good to include a summary of the race's special abilities in the answer; for those who don't remember which races are which by name.

Good point. But I think then that should be put in the question. And not each and every answer. :)

I wasn't sure whether it made more sense in the question or answer; either sounds good.

As a side note. We played Gaia Project last night. The layout looked Terran-friendly. I picked last, and the Terrans were still available, so I took them. 199 points. BUGGER! One point shy of 200 points. Still new personal best, though.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

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text:
Can Silent Gravestone prevent someone from casting an Aftermath spell from the graveyard?
A player has Silent Gravestone on the battlefield and the opponent has Commit // Memory in their graveyard, where Memory has Aftermath. Can they cast Memory and would it have its effect on the player with Silent Gravestone?
I don't see Memory targeting anything and couldn't find rules saying aftermath requires you to cast target card from the graveyard.

If you cast Memory from a graveyard, nothing is targeting a card in graveyard. Therefore Silent Gravestone won't prevent you casting Memory. When Memory resolves, both players shuffle their hand and graveyard into their library, then draw seven cards. Silent Gravestone only prevents the casting of a spell (or ability) that targets a card or cards in a graveyard.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
Do abilities that say "each player/opponent" target, and can I change who's affected?
If an ability that affects all players is used, then does that make each player a target of the effect?
I.e. Is Guttersnipe activated am I able to change the target of the ability?

No, only things chosen for the word "target" are targets.
One notable exception is Aura enchantments, which are cast targeting the thing you want to enchant even though the word "target" does not appear on them (rule 303.4a).

If you look at the reminder text of some auras, the full rules text of an aura does use the word target. It is just for some reason they removed that reminder text from new core sets, you still see them in 8th edition auras.


text:
Can you enchant yourself with an aura that enchants a permanent?
I'm relatively new to MTG so maybe I'm way off, but I can't find any conclusive answers nor official rulings on the following:
If one can enchant a permanent,
and a planeswalker is considered a permanent,
and the player is considered a planeswalker...
Can you enchant yourself? It sounds ridiculously overpowered (you could do such insane things as turn yourself into an indestructible artifact) but I can't find any real reason you wouldn't be able to

What do you think turning yourself into an indestructible artifact would do? Even if you could do that, it wouldn't do anything beneficial.

It was just an example, but one could argue it could make you immune to something like Door To Nothingness. Or imagine casting hexproof on yourself. If such things were possible you could definitely play some interesting moves.

It's important to note that keywords have specific meanings though. For example, "Indestructible" would not prevent game loss. It specifically means "A permanent with indestructible can’t be destroyed" and nothing else. "Destroyed" also has a specific meaning, and losing a game is not being "destroyed". Magic is full of very specific terms like this, so it's important to not think about 2 things as basically the same just because they have similar meanings in English.

Oh, and you can give yourself Hexproof with several different cards. :) See here

Imagine becoming tapped, and having to play lying sideways on your chair.

The player is a "planeswalker" only in lore terms. As far as game mechanics are concerned, "planeswalker" has a defined meaning, and a player is not a planeswalker.
A planeswalker in the mechanical sense is a type of object, a game entity that interacts with players and other objects:

102.1. A player is one of the people in the game. [..]
109.1. An object is an ability on the stack, a card, a copy of a card, a token, a spell, a permanent, or an emblem.
110.4. There are five permanent types: artifact, creature, enchantment, land, and planeswalker.

So when an aura can enchant a (type of) permanent, then that does not include players, and vice versa. There are auras that can enchant players, but the aura will always say so specifically. Here are all auras that can enchant players, and here are all auras that can enchant planeswalkers.

Makes sense, it seemed fairly gamebreaking to me that the physical players themselves appeared to have no real distinction from other aspects of the game.

Players are not planeswalkers, nor are they permanents, so the examples you provide don't work.  The player as a planewalker was a flavor-only description, but it has no truth within gameplay.
There are some specific enchantments that "Enchant Player" (many have the subtype Curse).  You can enchant yourself with these auras, but you probably wouldn't want to for many of them.


text:
Can Arlinn Kord's -1 ability target planeswalkers?
Can Arlinn Kord's -1 ability (deals 3 damage to target creature or player) target another planeswalker?

Always read the Gatherer text of cards, not the text printed on the card.

Yes, it can. In fact the text has been errataed to say:

−1: Arlinn, Embraced by the Moon deals 3 damage to any target. Transform Arlinn, Embraced by the Moon.

“Any target” means any creature, player, or planeswalker.
Before Dominaria, we had a rule called the planeswalker damage redirection rule: it meant when we were dealing damage to a player with a spell or ability, we could make that damage hit one of their planeswalkers instead.
Dominaria removed that rule, and any pre-Dominaria card that said “target creature or player” now says “any target” to remain functionally the same. There are a few other changes that were made too: you can read about those in Dominaria Oracle Changes under the “Planeswalker Damage Redirection” heading near the start.
If you see a card from before Dominaria that says “target creature or player”, it now has errata to say “any target” instead.


text:
If I can cast sorceries at instant speed, can I use sorcery-speed activated abilities at instant speed?
So Teferi, Time Raveler is down, and I have +1'ed him. I may now "cast sorcery spells as though they had flash". My Adorned Pouncer is in the graveyard, and can be Eternalized "only as a sorcery".
Does this mean I can Eternalize at instant speed? I feel like it shouldn't but would love a rules clarification.

Hmm, this is a dupe but might want to close the other question after comparing answers

I did have a look, and there were similar questions, but I didn't feel they quite gave me the clear answer I was after. My question is also more generally worded, so would hopefully be more obvious to fellow seekers.

Yup, I think your question is more generally worded and has better answers. That is why I think the other question should be closed and this one made a target. Now that it is closed though it will probably take a moderator to switch them.

No, Teferi only affects sorcery spells. This is because the phrase “any time you could cast a sorcery” (or “do this only as a sorcery”[see note]) doesn't actually mean any point you are able to cast a sorcery spell, but instead it means whenever it's a main phase of your own turn and the stack is empty:

307.5 If a spell, ability, or effect states that a player can do something only “any time they could cast a sorcery,” it means only that the player must have priority, it must be during the main phase of their turn, and the stack must be empty. [...]

To confirm this we can take a look at the rulings on Hypersonic Dragon which has a similar ability:

You may cast sorcery spells as though they had flash. (You may cast them any time you could cast an instant.)

One of its rulings says:

Hypersonic Dragon’s last ability has no effect on abilities that you can activate “any time you could cast a sorcery.” (2017-11-17)

There is no card that generally provides instant timing to abilities that can only be activated “any time you could cast a sorcery”, and such a card will probably never appear.
There are cards that let you activate specific sorcery-speed abilities at instant speed. Leonin Shikari lets you use Equip abilities with instant timing, Teferi, Temporal Archmage does the same for loyalty abilities. However there is nothing that lets you eternalize at instant speed.

Note: Eternalize says “Eternalize only as a sorcery” in its reminder text. This “do thing only as a sorcery” phrase is a short-hand for “any time you could cast a sorcery” that you may see in reminder text. (You'll see the same short-hand used for Equip abilities such as on Explorer's Scope.) The full text for the Eternalize ability is as follows:

702.128a Eternalize is an activated ability that functions while the card with eternalize is in a graveyard. "Eternalize [cost]" means "[Cost], Exile this card from your graveyard: Create a token that's a copy of this card, except it's black, it's 4/4, it has no mana cost, and it's a Zombie in addition to its other types. Activate this ability only any time you could cast a sorcery."

Thanks, I knew there had to be a rule somewhere. It might be good if you could add an example of an effect that would allow this (or else to specify that none exists), if you happen to know this, just as an additional clarification/contrast, but realise this is beyond the scope of the question.

I've added that. I don't believe there is one.

Such an effect would not make much sense. Activated abilities are by default instant speed, and restricting them to sorcery speed is the rare exception. Adding an effect that creates an exception to the already rare exception would have an infinitesimal impact on the game, one that is certainly not worth spending a card on in the design stage.

@Hackworth I agree completely. I doubt we'll ever see such a card. I also checked to see if there was specifically a card that would say you could eternalize at instant speed, like Leonin Shikari is for equipments, and found none (using this search).

But it says "as a sorcery", not "any time you could cast a sorcery".

@Acccumulation Same thing. I've added a note about that.

@Acccumulation this confusion is precisely why I felt the question was warranted, so hopefully the answer here will be of value to others.

No.
There is a difference between casting a sorcery and activating an ability.
Teferi allows you to cast a sorcery even if the stack is not empty, it won't allow you to activate an ability that has the "sorcery" restriction.
Even though previously used wording of "any time you could cast a sorcery" can be written on the card, this means, any time during your main phase when the stack is empty.

307.5 If a spell, ability, or effect states that a player can do something only “any time they could cast a sorcery,” it means only
  that the player must have priority, it must be during the main phase
  of their turn, and the stack must be empty. [...]


text:
Tiana, Ship's Caretaker and Kaya's Ghostform
Tiana, Ship's Caretaker is a somewhat unique effect that lets all auras and equipment that go to your graveyard return to your hand.
Kaya's Ghostform will bring a creature or planeswalker back from the graveyard or exile to the battlefield.
So what exactly happens when Kaya's Ghostform is enchanting Tiana, and Tiana dies?
I think the most likely scenario is this:

Tiana dies.
Ghostform trigger goes on the stack, and Ghostform goes to the graveyard as a state-based action.
Because Tiana was not on the battlefield when Ghostform entered the graveyard, it is NOT returned to hand.
Tiana is returned to the battlefield.

Obviously, I'd prefer it if I get both back, so I'm hoping someone here can prove me wrong.

Gatherer for Tiana says "If an Aura you control is put into a graveyard immediately after Tiana leaves the battlefield, most likely because Tiana left the battlefield but the Aura was put into the graveyard as a state-based action after it found itself not attached to anything, Tiana’s last ability won’t trigger."
Your reading is correct, and step 3 is the crucial bit of info. When Tiana herself dies, the game checks for state based actions when the next player gets priority. The game would see a Ghostform attached to nothing, then it would move to the graveyard. At this point Tiana is no longer on the battlefield, so her last ability will not trigger according to the Gatherer ruling.
Additionally, please note that the Tiana returning due to Ghostform is a new object according to the game. The new Tiana has no memory of the the old Tiana or its auras. To conceptualize this, if you play Languish and then Grizzly Bear on your turn, your Grizzly Bear lives. Languish only affects the creatures already on the battlefield when it is played. By the same logic, Tiana only sees the auras and equipment that go to the graveyard when it's actually on the battlefield.
You would get both back if both Tiana and its enchanted Ghostform were destroyed simultaneously, such as by Planar Cleansing. Spells with multiple targets such such as Causalities of War also produce the same effect as Planar Cleansing. In both of those cases, Tiana is on the battlefield when the aura is destroyed, so her last ability will trigger. You get a Ghostform trigger immediately and Tiana sets up a delayed trigger for your end step. Both happen simultaneously, yet the triggers themselves are independent. Ghostform returns Tiana to the battlefield immediately, while Tiana's delayed trigger goes on the stack during your end step and returns Ghostform to your hand. Gatherer confirms this ruling.

Thanks for the complete answer. Probably should have checked the oracle text before posting!

Perfectly fine, it's not obvious.

This is exactly what will happen. If the effect that kills Tiana doesn't also destroy the Ghostform, but rather the Ghostform goes into the graveyard as a result of not being attached to anything, then Tiana won't be around to see the Ghostform die. She will die strictly before the Ghostform, and not be back on the battlefield until after the Ghostform has died.


text:
Can I use an instant speed Act of Treason effect to take a Seedborn Muse and use its ability?
Can I trigger an instant speed “Act of Treason” type effect (like with a Vedalken Orrery or Jeering Instigator, for example) to grab a Seedborn Muse before an opponent’s untap and untap all my permanents?

In case you wonder why the answers focus on being able to cast a spell before the untap step: You can't cast in response to Seedborn Muse's ability (because its not a triggered ability but a static ability that creates a replacement effect that modifies the rules), and it  wouldn't help help to change the controller of a source of a triggered ability after it has already triggered anyway (since that doesn't change the controller of the ability).

Whether or not I could cast a spell (or trigger an ability- in the case of jeering instigator) before the untap step is the crux of my question.

Mainly, I’m trying to figure good possible uses of the “act of treason” effect when you can do it on opponents turns. Other than the obvious one, where you pull an attacker out of combat and use it to block a different attacker- hopefully resulting in a two-for-one.

Well, obviously there will be points in the game prior to your opponent's untap step. For instance, on the turn before your opponents turn, you can grab the Seedborn Muse during the ending phase. If that's your turn, you can announce after your second main phase "I am casting Act of Treason using Vedalken Orrery's ability". Or, if you're in a multiplayer game, if that's another player's turn, then when that other player announces the end of their turn, you can say the same; when a player says they're ending their turn, they're just passing priority, and other players have the chance to take actions before the turn actually ends.
However, there are two problems.
First, Act of Treason only lasts until end of turn. If you do this during the end step you will pass Seedborn Muse back more or less immediately after it. You will not have Seedborn Muse by the time the next turn starts and it will be back under the control of whoever had it last.
Second, once the untap phase begins, it's too late to do anything to affect what happens in the untap phase. Even when something is "instant", you still have to wait until you receive priority, and

No player receives priority during this step so spells or abilities cannot be played. — Rules for the Beginning Phase

You first receive priority during your Upkeep, by which time Seedborn Muse has already had its effect and it is too late for gaining control of it to do much for you.

You're correct that you can cast whatever spell on a different turn, before Seedborn Muse's ability applies, but I think you should address the fact that if you do so with an Act of Treason-type effect, the control-change ability will unavoidably end during that same turn. Also, I don't think you understood what the card Vedalken Orrery does.

I have updated this to (a) accurately reflect the interaction with Vedalken Orrery, since it is not an activated ability and therefore saying it is activated would be incorrect, (b) point out the end of turn issue with Act of Treason.

There are ways to take control of a Seedborn Muse and use its ability to untap your permanents, but an effect that only lasts until end of turn like on Act of Treason won't help you there.
Seedborn Muse's ability happens during the untap step, the very first thing in a turn. You have no opportunity to act in that same turn before that happens. And if you use an effect like on Act of Treason or Jeering Instigator to take control of the Seedborn Muse on a previous turn, that effect giving you control of it will end during that same turn, so it will be back under its owner's control by the time you get to the next untap step. You would need a longer-term control effect like Control Magic to actually be able to use the Seedborn Muse's ability.

Thanks for the answers. My question was primarily about whether or not instant speed effects can resolve before untap.

The rules reference from doppelgänger was very helpful. I was using the term trigger- not as a descriptor of the ability but just to mean “initiate.” Because in one example (jeering instigator)- I’m using a triggered ability, while in the other (Vedalken Orrery)- I’m using a static ability to cast a sorcery with flash- but in both cases I’m using the effect at instant speed. I was under the impression that “flash” allowed cards to resolve at instant speed.

Does vedalken Orrery only allow casting at instant speed- but non-instant spells still resolve last?

In what way did "Seedborn Muse's ability happens during the untap step, the very first thing in a turn. You have no opportunity to act in that same turn before that happens" not address the questions you are bringing up in the comments?

In what way did my comments/ further questions imply my original question was unanswered?

I was asking a further question about “flash” based on a reply that I didn’t understand how Vedalken Orrery works.

That's how this site works. If you want clarification on an answer, you comment on the answer. If you instead have a new question, you should ask a new question as a separate post. Also, I didn't say you didn't understand Vedalken Orrery. That comment was addressed to the author of the answer it is attached to.

@Grenzo Winzo, Re "Does vedalken Orrery only allow casting at instant speed- but non-instant spells still resolve last?", That question make no sense. There's no concept of speed in MTG. "At instant speed" is (unfortunately) used as equivalent to "as though it has flash", which refers to when a spell can be cast or an ability can be activated, and it has nothing to do with the resolution of spell and abilities. If you have questions about when one can cast instant and non-instant spells, or if you have questions about how spells and abilities resolves, feel free to ask a new Question.

@ikegami thanks- I sort of thought that, but wasn’t sure because I was confused about a comment about not understanding how Vedalken Orrey works.

Turns out, that comment wasn’t directed at me.


text:
Should A Big Parasol on a Decidueye Protect me from Dragapult VMAX Shred
Can anyone help clear up an discussion I'm having with my son as to whether a big parasol stops a dragapult's shred getting through Deep Forest Camo.
The Text on Decidueye's Deep Forest Camo ability is:

Prevent all damage done to this Pokémon by attacks from your opponent’s Pokémon V and Pokémon-GX.

The text on Big Parasol is:

As long as the Pokémon this card is attached to is in the Active Spot, prevent all effects of attacks from your opponent’s Pokémon done to all of your Pokémon. (Existing effects are not removed. Damage is not an effect.)

And the text on Dragapult VMAX's Shred Attack is:

This attack’s damage isn’t affected by any effects on your opponent’s Active Pokémon.

So does the big parasol prevent the effect of the attack that is it's ability to get through effects? My assumption is no as "Damage is not an effect" but my son's point is that the effect is that it ignores effects.  I can see what he's getting at but as shred would ignore other tool cards (e.g. Hard Charm) I can't see that the big parasol should stop it.

The direct answer: Dragapult VMax's attack goes through.
The way to understand it:  Big Parasol puts a "shield" on the Pokémon, so that it doesn't allow anything other than damage go through that shield. That's great!  But in this case, that's all that is being passed: damage.  Decidueye's ability ("prevent all damage done to this Pokémon...") is an effect on Decidueye, and it (attempts to) affect something to the damage being dealt to Decidueye ... but it doesn't actually work, due to Dragapult VMax's attack text that says to ignore that effect. Big Parasol doesn’t come into play.

If anyone remembers where the Compendium references are for this, please feel free to edit them in - I can't find them, as they're under something else (Big Parasol has one entry, but it's not relevant).

The other answer is correct- Draga's dmg from shred hits Decidueye. Their explanation isn't quite right, though. Deep Forest Camo puts an effect on Deci, not the attacker. Deci gets two shields when it has a Big Parasol- now V damage AND effects from attacks can't hit it.
The rub is that Draga VMAX's Shred attack doesn't affect Decidueye- it affects what it says on the card "the damage from this attack" is the subject of the sentence, so that's what's being affected. Big Parasol says prevent effects done "to your pokemon" Shred has an effect done to its own damage.

Yes, you’re right … didn’t explain it very well back then!! Adjusted the wording some. I find it very hard to explain Shred interactions satisfactorily even though I know how they work…


text:
How can I make Wall of Roots's toughness 0 and still sacrifice it?
In the ruling about Wall of Roots is written the following:

2017-11-17: If you must sacrifice a creature to pay a casting or activation cost that also includes mana, such as that of Bubbling Cauldron’s abilities, you may put a -0/-1 counter on Wall of Roots to make its toughness 0 and then sacrifice it to pay that cost.

I do not understand this properly. Compared to the state based actions this seems wrong. You would get the mana and then the creature dies. Mana ability are for normal not using the stack, and can't be responded to. But this is a mana ability, and a 'put a counter on a creature ability'. Does that mean, that the 'put the counter ability' is still on the stack, when you already got the mana? A creature can't have toughness 0 and then become sacrificed.
I hope someone can explain to me this strange card.

This ruling describes an unusual interaction with Bubbling Cauldron, which says:

{1}, {T}, Sacrifice a creature: You gain 4 life.

Specifically it requires mana and a creature sacrifice, and that ruling is attesting that you can use Wall of Roots for both. This is because of two quirks of the game:

State-based actions are only checked when a player gets priority. This means they are not checked during the process of putting a spell or ability on the stack; they are just checked before and after. (The same is true for whilst a spell or ability is resolving, but that's not so relevant here.)
Wall of Roots's ability is a mana ability, and mana abilities can be activated during the process of putting a spell or ability on the stack. They do not themselves use the stack and simply immediately resolve.(1)

The process works like this:

You announce you're activating Bubbling Cauldron's ability.
During the process of activating the ability, because the cost includes a mana cost, you may activate mana abilities. You activate Wall of Roots's ability, pay its costs (put a -0/-1 counter on it, reducing it to 0 toughness), and add one green mana. It will now die the next time state-based actions are checked, but they're not going to be checked yet.
After activating mana abilities you may now pay costs. You pay the one green mana and sacrifice Wall of Roots.
The process of activating the ability is now finished. State-based actions are checked. If there's a creature with 0 or less toughness, it will now die, but there isn't one anymore.

You can do the same thing with other spells or abilities that require both mana and a sacrifice as part of their cost, such as Eldritch Evolution or Evolutionary Leap.
If you were to reduce Wall of Roots to 0 toughness outside the process of casting a spell or activating an ability, it would immediately die as you expect, and you would not also be able to later sacrifice it.
(The citations above are from the procedure of casting spells. The rules for activated abilities say that we announce we're activating the ability, and then follow the spell casting procedure after that.)

(1) From these rules in the section on mana abilities:

605.3a A player may activate an activated mana ability whenever they have priority, whenever they are casting a spell or activating an ability that requires a mana payment, or whenever a rule or effect asks for a mana payment, even if it’s in the middle of casting or resolving a spell or activating or resolving an ability.
605.3b An activated mana ability doesn’t go on the stack, so it can’t be targeted, countered, or otherwise responded to. Rather, it resolves immediately after it is activated. (See rule 405.6c.)

Here is a simple search containing a lot of cards where this interaction might be relevant, specifically for casting.


text:
Can you negate an adventure spell?
Can I Negate the instant/sorcery part of an adventure spell?
Say, someone casts Stomp from bonecrusher giant. Can I negate it?

Yes, there is nothing special about the Adventure half of an Adventurer card while it is on the stack. Comprehensive rules 715.3b:

While on the stack as an Adventure, the spell has only its alternative characteristics.

Countering the Adventure half of an Adventurer card is often a very good play to make as the countered spell goes to its owner's graveyard, not into exile where the non-Adventure half of the card can be cast - e.g. if you counter Stomp, its owner does not get to cast Bonecrusher Giant from exile.
A small note on terminology: the spell does not have halves. An Adventurer card has alternative characteristics, and if cast with those alternative characteristics it is then a spell with solely those characteristics - e.g. what is on the stack is either the instant spell Stomp or the creature spell Bonecrusher Giant, not a split object with both sets of characteristics. This may seem pedantic but it can be important - for example, you cannot use Essence Scatter to counter Stomp, because it is not a creature spell.

Hmm, but as a card, it has all the characteristics of both options right? Ie, it is a creature card and an instant card? So, if there was some spell that let you exile a noncreature card from someone's hand, library, graveyard, or stack, then it wouldn't let you exile stomp?

@WillChen The very first point of Throne of Eldraine release notes answers that (in the negative).

@WillChen See also CR 715.4 "In every zone except the stack, and while on the stack not as an Adventure, an adventurer card has only its normal characteristics." - "normal characteristics" here refers to the non-Adventure half of the card.


text:
Can triggered effects occur even though a creature has summmoning sickness?
During my previous turn I had cast onto the battlefield Aven Wind Mage, which has the ability:

Whenever you cast an instant or sorcery spell, Aven Wind Mage gets +1/+1 until end of turn.

On their next turn, my opponent activated the ability of Siege-Gang Commander to deal two damage to my Wind Mage, attempting to destroy it:

{1}{R}, Sacrifice a Goblin: Siege-Gang Commander deals 2 damage to any target.

I responded to this with Dramatic Reversal:

Untap all nonland permanents you control.

even though I knew that all my creatures were already untapped. My opponent claimed that this was illegal as Aven Wind Mage has summoning sickness and does not get to trigger its ability, keeping it alive.
Who is correct in this situation - can I legally play Dramatic Reversal although there are no tapped creatures to untap and as a result give Aven Wind Mage the needed +1/+1 until the end of turn to keep it alive?

You are correct - summoning sickness is not relevant here as it does not prevent a creature's triggered abilities from triggering. It would prevent you from attacking with Aven Wind Mage, or paying costs with the {T} symbol, but you weren't attempting to do those things. See that linked question for the full details.
Another potential confusion in the play here is that it is perfectly acceptable to cast Dramatic Reversal even though it would not directly affect anything. By contrast if you had tried to cast Aerial Assault with no tapped creatures on the battlefield, this would not have be a legal play as that specifies

Destroy target tapped creature.

and you would not have been able to specify a valid target for the spell. The difference here is between an illegal play (one you're not allowed to do) and an ineffective play (one you're allowed to do but doesn't have any real effect).

He had the ability to attack any target with his 2/2 creature, so he used it against Aven Wind Mage as its a flyer.

@Spaciousmind Exactly which creature did they have? "Attack" is a very specific term in MtG, much more specific than "cause damage to".

Hi Philip, you are correct, I had think back to the proper series of events.  Opponent played a Goblin deck.  He used Siege-Gang Commander ability "Sacrifice a Goblin: Siege-Gang Commander deals 2 damage to any target.  (He had sacrificed a 1/1 Goblin Token Creature to activate this).

Keep in mind that by the same reasoning, your opponent can cast Siege-Gang Commander and then activate its ability the same turn, sacrificing one of the tokens it created on ETB.

@KarlKnechtel Yes, assuming they have the spare mana that's absolutely correct. But I don't quite see how it's relevant here?

It also prevents paying costs with the {Q} (untap) symbol.


text:
Can you attack in stages before blockers are declared?
I have Answered Prayers, which reads:

Whenever a creature enters the battlefield under your control, you gain 1 life. If Answered Prayers isn't a creature, it becomes a 3/3 angel with flying in addition to its other types until end if turn.

I declare an attacker, and in response to it attacking a creature enters the battlefield. (Say, Grave Titan creating its zombies.) Can I then attack with Answered Prayers as well before blockers are declared?

No. Basically, all attackers need to be declared at once:

Declare Attackers Step

508.1. First, the active player declares attackers. This turn-based action doesn’t use the stack. To declare attackers, the active player follows the steps below, in order. If at any point during the declaration of attackers, the active player is unable to comply with any of the steps listed below, the declaration is illegal; the game returns to the moment before the declaration (see rule 725, “Handling Illegal Actions”).
508.1a The active player chooses which creatures that they control, if any, will attack. The chosen creatures must be untapped, and each one must either have haste or have been controlled by the active player continuously since the turn began.

and the final step is the triggering of abilities:

508.1m Any abilities that trigger on attackers being declared trigger.
508.2. Second, the active player gets priority. (See rule 117, “Timing and Priority.”)

When they resolve, and Answered Prayers triggers and resolves in turn, it's too late to declare additional attackers.
Note that if you somehow get a second combat phase in that turn (such as with Relentless Assault), your Answered Prayers might be eligible to attack during that combat phase since it already became a creature during the first one. The exception is if you cast Answered Prayers this same turn, in which case it can't attack because it has "summoning sickness"; it isn't under your control since the beginning of your most recent turn.

I don't understand why you mention an extra combat phase in the last paragraph. If you trigger Answered Prayers the turn it came into play, it will be summoning sick, extra combat phase or not.

It's something that's often overlooked because it's not a creature when it enters the battlefield. Often enough to get mentioned in the rulings below the card in Gatherer, as I noticed after writing the paragraph.

It's not obvious that Answered Prayers was cast this turn. If it's been around (as an enchantment) all turn, it could attack in the hypothetical second combat phase

@Glorfindel I've updated the paragraph in a way I suspect reads better. Could you check it over and update/revert as you see fit?


text:
Can Taigam grant rebound to spells I already cast before his attack?
So, for example, if I cast Shock, and then during my combat step attack with Taigam, Ojutai Master, then after he attacks, cast another spell like Opt, would both Shock and Opt gain rebound as they were cast on a turn that the creature attacked? Or only Opt as it was cast after he attacked?

It would only count instants or sorceries that you cast after Taigam attacks.
Taigam's ability only triggers at the time that you cast an instant or sorcery, and at that moment it checks to see if he has attacked that turn. Each time you cast an instant or sorcery, his ability triggers if he has attacked that turn. Any instants or sorceries you cast when he hasn’t attacked that turn don’t meet the requirements for triggering.
Note that Taigam's triggered ability has an intervening if clause:

603.4. A triggered ability may read “When/Whenever/At [trigger event], if [condition], [effect].” When the trigger event occurs, the ability checks whether the stated condition is true. The ability triggers only if it is; otherwise it does nothing. If the ability triggers, it checks the stated condition again as it resolves. If the condition isn’t true at that time, the ability is removed from the stack and does nothing. Note that this mirrors the check for legal targets. This rule is referred to as the “intervening ‘if’ clause” rule.

This means that when you cast an instant or sorcery spell, if he hasn’t attacked this turn, the ability doesn’t trigger at all. But even if it were not an intervening if clause (such as “whenever you cast an instant spell, it gains rebound if Taigam has attacked this turn), then the ability still wouldn’t work in that case. It would trigger and go on the stack, but when it resolved it would have no effect because the condition wouldn’t be met.
In order to affect instants and sorceries that were cast before attacking, it would have to have a completely different wording; such as something that triggers when he attacks instead of triggering when you cast the spell.

"It would only count instants that you cast after Taigam attacks." Instants or sorceries.

@Acccumulation Fixed.

https://mtg.gamepedia.com/Rebound

From the Comprehensive Rules (July 3, 2020—Core Set 2021)
702.87. Rebound
702.87a Rebound appears on some instants and sorceries. It represents a static ability that functions while the spell is on the stack and may create a delayed triggered ability. “Rebound” means “If this spell was cast from your hand, instead of putting it into your graveyard as it resolves, exile it and, at the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.”
702.87b Casting a spell as an effect of its rebound ability follows the rules for paying alternative costs in rules 601.2b and 601.2f–h.
702.87c Multiple instances of rebound on the same spell are redundant.

[bolding added]
Once the spell resolves, it's not on the stack anymore (and in fact does not exist as a spell anymore). Since it's not on the stack, rebound doesn't apply. There's also the fact that when an object changes zones, it becomes a new object with no memory of the previous one. When a spell resolves it leaves the stack and enters the graveyard, and once in the graveyard it has no "memory" of being a spell that was cast on a turn that Taigam attacked.

I don’t see how this addresses the question. How rebound works doesn’t seem relevant at all; the question was whether the triggered ability would grant rebound in the first place. The question could be the same with a different ability that did something other than granting rebound (with the same triggering condition).


text:
Can you play multiple cards together of the same number but different colors?
During an Uno game, can one player put multiple cards of the same number but not the same color on top of each other, with the first card the same as the previous one in the Discard Stack?

You may only play a single card each turn and note the rules mention playing "a card" not multiple.
Rules

You have to match either by the number, color, or the symbol/Action. For instance, if the Discard Pile has a red card that is an 8 you have to place either a red card or a card with an 8 on it. You can also play a Wild card (which can alter current color in play).

What you are referring to is a common house rule in Uno, that you can play multiple cards of the same value in a single play.  This is not in the official rules of Uno, and as such, there is no canonical answer other than "this is not allowed".  However, having played under the house rule, it usually goes like this:

You can play multiple cards of the same value as a single play, even if they are different values.
The bottom card must match the value or color of the previous top of the stack, but beyond that, you choose the order of the other cards that you play.
If the cards are numeric, there is no effect other than you having played multiple cards.
If the cards are a special effect, that effect is applied multiple times

Draw 2 or Draw 4: the value adds together, so three Draw 2's means draw 6 cards
Skip: skip a number of players equal to the number of skips played
Reverse: reverse a number of times equal to the reverses played; this equates to no effect with an even number of reverses and a regular reverse effect with an odd number

You can't go out on a play of multiple cards.  You must keep one of them in hand, declare "Uno", and then try to play it next turn.

This house rule has the advantage of allowing players who have gotten many extra cards to have a better chance of coming back (as the more cards you have, the more you will likely have with the same number).
I have typically seen this house rule played with the additional rule:

If someone plays Draw 2s or Draw 4s against you, you can add any number of Draw X card of the same type to pass it on to then next player, with your cards adding to the total needing to be drawn (ex. someone plays two Draw 2s against you; you can play one Draw 2 to make the next player draw 6 cards).


text:
What amount of color overlap does intimidate require?
I would like to make sure I understand intimidate well. If I have a green and blue creature, I can block a green creature with intimidate, because my creature shares a colour with it, right? And generally, creature is able to block creatute with intimidate if it shares at least one colour with it, colours don't have to be exactly the same?

The colors don't need to be exactly the same. The creatures just have to overlap by at least one color.
The intimidate reminder text tells us:

Intimidate (This creature can’t be blocked except by artifact creatures and/or creatures that share a color with it.)

A green creature with intimidate can be blocked by any creature that is at least green, including a blue-green creature, or even just a mono-green creature, because it will share a color with them.
Likewise a blue-green creature with intimidate can be blocked by any creature that is at least green or blue: the blocker could be mono-blue, or green-red, etc. This means a five-color card like Progenitus is never intimidated by any colored creature with intimidate.
Naturally also artifact creatures can always block any creature with intimidate, regardless of their colors or lack thereof.

Technically, Progenitus is intimidated by colourless creatures with Intimidate. Progenitus is also only able to intimidate colourless non-artifact creatures (like eldrazi)

@StephenTG Thanks! Good thinking, I've corrected my post.

@StephenTG to be fair though, Progenitus with intimidate would be pretty redundant - protection from everything is pretty 'intimidating' already (effectively includes the same mechanical results and then some)

@Andrew Oh yeah, the colored/artifact creatures just won't be intimidated as they stand by and let the ol'worldsoul through


text:
Lochmere Serpent's ability
If I want to use Lochmere Serpent's first ability, can I tap an island for mana and sacrifice the same island?

{U}, Sacrifice an Island: Lochmere Serpent can't be blocked this turn.

Yes, you can do this.
All islands have the (unwritten) ability of Tap: Add {U} to your mana pool. You can activate this ability any time you have priority. You simply tap the land to get {U} in your mana pool, which will remain there throughout the current step/phase. You can then spend that {U} and sacrifice your now-tapped Island to pay your Serpent's ability cost.

You can even tap the island you want to sacrifice as part of the process of playing the ability, rather than beforehand (a non-priority possibility to activate mana abilities is part of the process of casting spells or activate abilities) (this is why some mana abilities have the restriction "only activate any time you could play an instant"). Doing it that way may be handy if, for instance, you want to circumvent certain triggered abilities, like Mine Layer


text:
Can joker be played with no other tiles?
When playing Rummikub, if you have joker tile, no other tiles to play with it and nobody has gone out can you use it any where on the board?

There is nothing in the rules that prevents you from playing a joker as a single tile, as long as you had your initial meld. It can be advantageous if another player is about to win and you don't want the 30 points penalty.


text:
How does shuffling work when your library is empty?
Say there are no cards in someone's library. Can they shuffle their graveyard and hand into their library with an effect that instructs them to do so, if there is technically no library to shuffle into?

Yes, you can still shuffle your library like normal even if it is empty. This includes both effects that shuffle your library normally, such as Entomb, and effects that shuffle your graveyard or hand into your library, such as Clear the Mind.

701.19e If an effect causes a player to shuffle a library containing zero or one cards, abilities that trigger when a library is shuffled will still trigger.

So there is no difference between shuffling an empty library or a non-empty library as far as game rules are concerned.

The library is a zone that can contain cards. An empty library is still a library, and an empty graveyard is still a graveyard - a zone still exist even when there are no cards in it.
There was a time where this exact scenario would happen, though mill wasn't very common at the time there were powerful mill cards that people did play, around the time of M11 when cards like Traumatize, Keening Stone with their powerful mill effects, particularly when combined, and when Emrakul, the Aeons Torn, Kozilek, Butcher of Truth and Ulamog, the Infinite Gyre were all in standard.
Milling out one of these big Eldrazi when Keening Stone was taking out the bottom half of the library would lead to the library being empty before everything was to be shuffled back in.
You can:

Shuffle your graveyard into your library when your library is empty.
Shuffle your graveyard into your library when your graveyard is empty.
Shuffle your hand into your library when your hand is empty. (like Time Reversal)
Search and shuffle your library when the library is empty.

We can see this from the comprehensive rules section on shuffling:

701.19c If an effect would cause a player to shuffle one or more specific objects into a library, that library is shuffled even if none of those objects are in the zone they’re expected to be in or an effect causes all of those objects to be moved to another zone or remain in their current zone.
701.19d If an effect would cause a player to shuffle a set of objects into a library, that library is shuffled even if there are no objects in that set.
701.19e If an effect causes a player to shuffle a library containing zero or one cards, abilities that trigger when a library is shuffled will still trigger.


text:
Does Commander Tax reset?
Example:

I cast my commander from my command zone, paying no tax.
Commander dies
Goes to command zone
Summon from command zone, paying tax (2)
I bounce my Commander to my hand, play him from hand
He dies a second time.

The next time I play him from the command zone is his tax (2) or (4)?

Note that to be accurate; you should avoid using the term "dies" here; because a commander that is sent to your command zone instead of your graveyard will not count as dying - things that say "whenever a creature dies" will not trigger, for example.

Strictly speaking, a commander can die. Moving it to the command zone instead of the graveyard is a choice the player needs to make. It is just commonly treated like the default behavior because it is almost always the right choice.

@murgatroid99 true it can die, but the process CefG is describing doesn't fit the game's technical definition of dying, since they are using the replacement effect choice.

It is entirely possible for a commander to die, and later go to the command zone, and then be played from the command zone.

I think it was clear enough from the question as originally worded that the user was talking about using the Commander rule to send the commander to the command zone instead of the graveyard. And I don't think my comment would be likely misread as saying that a Commander can never die.

The commander tax never resets, but it also doesn't count times when it isn't cast from the command zone; so you must pay an additional {4} in your case.

903.8. A player may cast a commander they own from the command zone. A commander cast from the command zone costs an additional {2} for each previous time the player casting it has cast it from the command zone that game. This additional cost is informally known as the “commander tax.”

The additional 2 per time it has been cast counts every time it is cast from the command zone.


text:
What's the lifetime of Wicked Wolf's +1/+1 counters?
Do Wicked Wolf's +1/+1 counters stay after the turn is over?
It says:

Sacrifice a food: Put a +1/+1 counter on Wicked Wolf. It gains indestructible until end of turn. Tap it.

I was reading the rules and it said that you can sacrifice foods to add counters to it even when it is tapped, but will the counters stay?

The counters will stay; "until end of turn" refers to gaining indestructible.
Note that you cannot "put a +1/+1 counter on Wicked Wolf until end of turn". Putting a counter on a thing is a specific act that happens in one moment; it does not work in English (or in MTG rules) to give it a duration. If a counter were going to be temporary, it would need a separate instruction to remove that counter at the end of the turn, like this:

Put a +1/+1 counter on Wicked Wolf. Remove it at the end of the turn".

I recall that " gains +1/+1 until the end of the turn." was a commonly used wording back when I played. A +1/+1 counter was always something permanent.

@MechMK1 I don't remember any card that does counters "until end of turn" because you can just do the effect "until end of turn" without the counter. Counters are permanent by default.

@Nelson Exactly. If an effect was meant to be temporary, it was always "[...] gains [...] until the end of the turn." The only "temporary" counters were effects like "When [...] is summoned, add X counters to it. Whenever [...], remove a counter. When no counters remain, [...] is destroyed" - or something like this. But even then the counters were not temporary; the effect specified when counters were to be removed.

You can have "exile permanent until end of turn", so I don't think it's legitimate to appeal to "English", as opposed to MtG rules (presumably, your argument would be that a counter is not an object, so is treated differently), to assert that this is not possible.

@MechMK1 That is still the standard wording for temporary pump effects.

There's a period at the end of the sentence

Put a +1/+1 counter on Wicked Wolf.

So the only ability it loses at the end of the turn is indestructible; the +1/+1 is permanent (that is, until it's removed by another effect, such as Vampire Hexmage's ability, or damage from a source with wither – a -1/-1 counter always cancels out with a +1/+1 counter).

The comment about wither could be misleading for someone still uncertain about how +1/+1 counters work, since the counters are technically removed not by wither, but by the interaction with +1/+1 and -1/-1 counters. Can you consider expounding your answer to explain why wither damage will result in removing +1/+1 counters? (or use a more straightforward example like Vampire Hexmage to demonstrate how counters could be removed)

It is also misleading because the cancellation of +1/+1 and -1/-1 counters is covered by a special rule.  No other type of counters cancel out (they are very rare though). So some of the older cards that use +2/+2 and -2/-2 counters will not have them cancelled out.

Counter rules specific for interaction of +1/+1 and -1/-1 counters, 122.3

The counters stay. The indestructible is until end of turn.
Note that the Ability itself is not a tap ability so it can be used as much as you have food tokens. But the ability itself causes it to tap so you can not defend with it when you use it in your turn, and it is not possible to buff it and attack with it before attackers are declared.
So the best thing to do is buff it and give indestructible while defending, or buff it if necessary before taking your own turn. This are always the better choices because this gives a lot more versatility with the food tokens too. (ex life gain, buffing or any other effect)

Also while thinking about the stack when attacking. If you attack with it, blockers are declared, and then using the ability, it is placed on top of the stack so resolves first. This causes it to tap first, and the attack is not happening if i am correct? So this will be another waste of this ability.

as soon as your creature is declared as attacker (and tapped), it is attacking. Declaring attackers (or blockers) isn't something that goes to the stack. Tapping an attacking creature, whether it's already tapped or not due to attacking, doesn't remove its attacker status. Attacking with the wolf, and using or not its ability depending on what's blocking is a valid strategy. The rulings on Gatherer specify explicetly you can use the ability when it's tapped anyway


text:
Is Leyline of Combustion triggered by attacks?
If my opponent attacks me, does that trigger Leyline of Combustion to do damage to them? I'm new and need help with this rule. Thanks

No.
Attacking is not casting a spell or activating an ability. It is a separate thing completely. Also, targeting has a specific meaning in Magic; just because you are going after a player does not mean are targeting them.
See here for more details about what things deal with targeting.


text:
Golos activated ability and adventure cards
If Golos, Tireless Pilgrim's activated ability were to hit a adventure card are you able to cast the adventure side of the creature or only the creature for free? Rules on Golos say you may not use alternative costs, and rules on adventure state an adventure is alternative characteristic. Is this the same thing worded differently?

You can do both.

715.3. As a player casts an adventurer card, the player chooses whether they cast the card normally or as an Adventure.

Playing a spell is the same as casting it. You're right that the adventure mechanic does mention alternative characteristics, but this is different from alternative costs.

118.9. Some spells have alternative costs. An alternative cost is a cost listed in a spell’s text, or applied to it from another effect, that its controller may pay rather than paying the spell’s mana cost. Alternative costs are usually phrased, “You may [action] rather than pay [this object’s] mana cost,” or “You may cast [this object] without paying its mana cost.” Note that some alternative costs are listed in keywords; see rule 702.

Yes, you can cast either part for free.
When you cast the spell, first you choose if you are casting the creature or the adventure. After you make that choice; you apply alternative costs; which includes “without paying their mana cost”. Nothing in Golos’s ability is restricted to applying only to creature spells or sorcery/instants; so it would apply to either.


text:
What happens when a land attacks then stops being a creature?
The card Nature's Revolt is out, then a mountain and is declared as an attacker, then the enchantment is destroyed.
What happens to the mountain? Is it still attacking, can it be blocked e.t.c.

The mountain will be removed from combat; which means it stops attacking, blocking, etc.

506.4. A permanent is removed from combat if it leaves the battlefield, if its controller changes, if it phases out, if an effect specifically removes it from combat, if it’s a planeswalker that’s being attacked and stops being a planeswalker, or if it’s an attacking or blocking creature that regenerates (see rule 701.14) or stops being a creature. A creature that’s removed from combat stops being an attacking, blocking, blocked, and/or unblocked creature. A planeswalker that’s removed from combat stops being attacked.

Question has been edited by the asker. Please edit your response to accomodate the edits, as this one is no longer relevant to the question

I feel like changes the question enough that it should be asked as a separate question; and this one rolled back....

Hmmmmm.... Probably true. Even so, shouldn't you still get rid of the answer if it is no longer relevant to the existing question?

Since the question was edited so soon after asking; I've just gone ahead and updated my answer to answer the new question.

Seems fair enough :D

Yes, the card can be blocked. The card would count as a creature, that in this situation, is attacking. Unless you decided to enchant it or use a spell that causes otherwise, the land would be able to be blocked, as well as block.

I think maybe you missed the part of the question where the Nature's Revolt, which is making the land a creature in the first place, is destroyed after attackers are declared.

The idea of the question is that the land STOPS being a creature before blockers are declared. Could you maybe consider editing or deleting this answer due to irrelevancy?


text:
Does Guttersnipe's ability count as attacking?
Does Guttersnipe dealing damage to a player from an instant being played count as it attacking you and therefore triggering Revenge of Ravens?

Related; though not a duplicate: https://boardgames.stackexchange.com/questions/48995/is-leyline-of-combustion-triggered-by-attacks

No, Guttersnipe's ability does not count as "attacking".
In Magic the word "attacks" as used on Revenge of Ravens specifically refers to declaring a creature as an attacker in combat. Guttersnipe's ability does not do that; it just deals damage to players.

To add on to this:
It's a good rule of thumb to read into the wording very literally. Modern Magic (including updated oracle text of old cards) is very specific about its wording. "Attack" has one very specific definition, and cards that check for "attacking" only apply to that specific definition. Same goes for casting, drawing, targeting etc. The only thing to watch out for are keyword abilities and card properties that don't include reminder text such as "303.4a An Aura spell requires a target, which is defined by its enchant ability" which is implicit on all auras but not written in text.

I believe that if a card says "Put this on the battlefield attacking", that's not attacking either.

@Acccumulation It's a subtly different reason. Revenge of Ravens checks in the declare attackers step, and that's also the earliest point that "Put this on the battlefield attacking" would go on the stack. RoR doesn't re-check once those resolve.

@Caleth Yeah, I should have said "Does not count as being declared as attacker".

The word attack in magic is very, very specific to a creature being an attacker in the combat step. Any other source of damage is not attacking, be it fight, tap to deal damage, or any other less common effect.
For the purpose of "whenever a creature attacks" it's even more restricted, there are effects that create creatures already attacking, like Hero of Bladehold, these tokens created "tapped and attacking" were never declared as attackers, so they get by the restrictions from things like Crawlspace and do not trigger things like Revenge of Ravens.
This trigger is talked about in the comprehensive rules:

508.3a An ability that reads “Whenever [a creature] attacks, . . .” triggers if that creature is declared as an attacker. Similarly, “Whenever [a creature] attacks [a player or planeswalker], . . .” triggers if that creature is declared as an attacker attacking that player or planeswalker. Such abilities won’t trigger if a creature is put onto the battlefield attacking.


text:
What does "starting life total" mean, and why do cards say that instead of saying a number?
At the end of Happily Ever After, it refers to your “starting life total” (emphasis added):

At the beginning of your upkeep, if there are five colors among permanents you control, there are six or more card types among permanents you control and/or cards in your graveyard, and your life total is greater than or equal to your starting life total, you win the game.

When referring to the “starting life total”, why doesn't it say “20 life” instead? Are there ways to change the starting life total?
Or, more likely, does the card say this in order to adapt it to different game formats? Would the “starting life total” be 30 in Two-Headed Giant, and 40 in Commander, and so on?

The starting life total depends on the format. In the Vanguard format, each player can even have different starting life totals. Happily Ever After refers to the actual starting life total used in each game.
As you correctly noted, different formats can have different starting life totals. To keep Happily Ever After balanced for all possible formats, its template uses the generic "starting life total" instead of the 20 that the most common formats use.
Most formats have a defined starting life total. The Vanguard format has "20 plus the used Vanguard card starting life total modifier".
Except for the already mentioned, oversized Vanguard cards that are clearly recognizable as such and that are only legal in the Vanguard format, there are no cards in the game that can change a player's starting life total.

103.3. Each player begins the game with a starting life total of 20. Some variant games have different starting life totals.
103.3a In a Two-Headed Giant game, each team’s starting life total is 30.
103.3b In a Vanguard game, each player’s starting life total is 20 plus or minus the life modifier of their vanguard card.
103.3c In a Commander game, each player’s starting life total is 40.
103.3d In a two-player Brawl game, each player’s starting life total is 25. In a multiplayer Brawl game, each player’s starting life total is 30.
103.3e In an Archenemy game, the archenemy’s starting life total is 40.

Does anyone even play Vanguard anymore? Commander might be a more relevant primary example.

I think he just brought of Vanguard as an example of a format where starting life totals aren’t a fixed number defined by the format; but can change every game.

Note that some cards used to just list an amount of life (e.g., Serra Ascendant) and then turned out to be hugely powerful in games where the starting life total is not 20. Switching to a template that refers to the "starting life total" makes these cards adaptive to the situation.

However, the thing that interests me most about this question is to have clarified that there is no way to "increase or decrease the starting life total at the beginning of the game", perhaps with some strange and mysterious card that could allow it, and that I don't I know. The main purpose of this question was this. The rest was already intuitive, and in any case confirmed by the good answer received.Thank you very much.

Felidar Sovereign is an example of a card that references a specific life total, and it's easy to see how it is an unbalanced win-con in a format like commander compared to modern.

They used to just list a number, but those cards were incredibly broken when played in other formats. There is no way to change a starting life total once the game has actually started, but different formats have different starting totals.
Take Serra Ascendant which is a 1/1 creature with lifelink for . It has an ability, " As long as you have 30 or more life, Serra Ascendant gets +5/+5 and has flying." This ability is incredibly powerful in Commander/EDH or two headed giant(2HG), since if Serra Ascendant is your first turn play, it's a 6/6 with flying and lifelink for a single mana! Now if they had written it as "As long as your life total is at least 10 higher than your starting life total [...]" Serra Ascendant wouldn't turn on until your life total was 50 in EDH or 40 in 2HG, taking away that immediate power it has in those formats.
Felidar Soverign has the same problem, it's a win condition if you have 40 life or more at the start of your turn. That's the starting life total in EDH, and only 10 points higher in 2HG. Getting a  out in those formats quickly isn't impossible, though it will take a few turns, all you have to do is maintain your life total, a lot easier than gaining 20 life. Now if it had been written as "At the beginning of your upkeep, if you have double your starting life total, you win the game." it would take 80 in EDH and 60 in 2HG, bringing back the balance it had in the usual constructed formats.
Remember Commander wasn't designed by Wizards of the Coast, it was originally called EDH and made by players, only adopted as an official format when it became popular, these cards were designed with only 20 point starting life totals in mind. Vanguard was never played very heavily, though players in that format could have a starting life total from 12 (Ashnod, at -8) to 38 (Gix, at +18) and was pretty much a failed experiment as far as formats go, no one looked at it for card design. Once EDH became pretty much the most popular format for Magic, they had to start considering starting life totals that were higher than 20 for card design, that meant no more talking about life totals as static numbers, but relative to whatever that different starting point would be.


text:
How would casting a Lightning Bolt in response to Giant Growth work in early Magic?
In early Magic—in the early nineties—the rules had a rule that made damage occur on the stack. I'd like to know how a certain situation (described below) would work in the rules at that time:

I have a vanilla 2/2.
Having priority, I cast Giant Growth on it.
My opponent, in response to Giant Growth, responds with Lightning Bolt targeting the vanilla.

What happened under those rules?

Thanks to Giant Growth, Vanilla managed to survive, due to the fact that  damage went on the stack, and therefore even if vanilla suffered three damage, it could immediately take advantage of the +3 increase in toughness since Giant Growth is still on the stack.

Or, did the fact that lightning was thrown in response to the Giant Growth automatically lead to the vanilla being sent to the graveyard? (just like the current game)

Even if it may seem trivial, I know for sure that lots of people have actually interpreted the early rules such that the vanilla survives the lightning. I want to verify this is the authentic way it plays, and not a completely mistaken interpretation.

Related: Can someone explain the Damage on the Stack rule change?

The obsolete rule that concerns "damage on the stack" only relates to combat damage. I still intuitively and subconsciously plan combats as though that rule is in effect, and have great issues correctly calculating, say, sacrificing attackers or blockers to activate abilities. (A creature of mine can't both deal its combat damage, be destined to die by the damage it's going to receive, and also be sacrificed to feed something like Arms Dealer. But it could back in my more active days, and I'm not used to that.)

Ooh ... @Doppelgreener again! Please let users and old players have a little more fun with this great site, and, above all ... let ME have some more fun, too !! Wasn't it funny to refer to Giant Growth as The Big Mice, thus recalling the first historical illustration of this card? Stack Exchange in my opinion is not, and should not be, an encyclopedia, As you think, doppelgreener. Encyclopedias are boring, while SE should be able to provide information but still having some fun doing it, just like the games it deals with.

Anyway, thank you very much...I have to admit that the editing is pretty good. Although I would prefer that users were left free to write their questions without them being continuously edited by more accredited users. Isn't it a right of users to refuse editing done by others?

@ManoFromBerlin Clear communication is important here. We can have fun, but we shouldn't be having fun at a cost of clarity. We may not be an encyclopedia, but we're supplying a function similar to one: we're building up a knowledge base of future reference for others to read and we owe those users a good and clear reading experience.

This depends on what era of the game you reference:

Pre-Sixth Edition (1993-1999), which used the batch.
Sixth Edition (1999) and onwards, which introduced the stack.

Your question referenced the early nineties, but also references the stack. The stack didn't exist in the early nineties, and without it neither did the damage-on-the-stack rule. It's not clear which era you're interested in so I'm going to address both of them.
Pre-Sixth Edition and the Batch (1993–1999)
The vanilla survives.
The MTG Wiki gives us a summary of the batch from the Fourth Edition rules booklet:

Batch (Obsolete)
A series of non-interrupt fast effects that build on one another as players respond to each other's spells. Batches are resolved by first-in, last-out for all effects. Any damage done to creatures or players isn't applied until the end of the batch, but creatures that are destroyed through means other than damage are sent to the graveyard immediately and regeneration and/or death effects are checked when this occurs.
— From the The Pocket Players' Guide for Magic: The Gathering - Fourth Edition (1995)

In Alpha, both Giant Growth and Lightning Bolt were instant spells and therefore used the batch. (As opposed to interrupts, which would play out differently.)
Essentially, the nature of the batch would be that we resolve the entire thing in one go, most recent first... but apply damage only at the end! That gives us the following outcome:

We begin resolving the batch. Lightning Bolt resolves first, because it was cast last. Its damage is not applied yet.
Giant Growth resolves, and the vanilla gets +3/+3.
The batch ends. The damage from Lightning Bolt is applied only now. The vanilla is now a 5/5 and survives the 3 damage.

This means your first bullet point, while referencing the stack, sounds unintuitive and incorrect—because you're actually describing what happens with the batch instead.
Side note: What would change if one of these spells was an interrupt?
The behaviour of an interrupt was to resolve immediately, instead of waiting until we start resolving the batch. If Lightning Bolt was an interrupt, it would actually be able to apply its damage before Giant Growth applied its effect, which would kill the vanilla. (If Giant Growth were an interrupt, there'd be no overall difference in outcome.)
Sixth Edition and the Stack (1999 onwards)
The vanilla dies.
The concept of the stack was introduced with Sixth Edition on 21 April 1999. Thanks to the Wayback Machine and Venser's Journal we have an archived copy of the 23 April 1999 Comprehensive Rules. Reviewing it, we can see that damage is only put on the stack as part of the combat damage step. Spells just deal their damage immediately as part of resolution:

408.2. Actions That Don't Use the Stack
408.2a Effects don't go on the stack. When a spell or ability resolves, its instructions are executed immediately.

This means we get this outcome:

Lightning Bolt resolves first, because it was cast last. It deals 3 damage to the vanilla.
We check state-based actions (rule 420) and the vanilla is destroyed & sent to the graveyard for having lethal damage (rule 420.5c).
We try to resolve Giant Growth, but it has no valid target remaining and is countered (413.3).

That's what we'd expect today, with the exception that Giant Growth would simply fail to resolve instead of being countered (because of Dominaria's rules changes in 2018).

And even if damage from spells also went on the stack like combat damage used to; it wouldn’t matter in this case. Lighting Bolt would resolve, and its damage would go on the stack on top of Giant Growth. Then the damage would resolve, killing the vanilla.

Under the stack rules, Giant Growth would have been countered as you say in 6th edition, but that’s not what would happen today; under current rules Giant Growth fails to resolve but is not countered.

Apart from the timing of damage effects, was there some other difference between the olden batch and the current stack? The answer says "we resolve the entire thing in one go", so is the difference that it wasn't possible to add new spells to the batch after part of it had resolved? (And I've actually played it in 4th ed. times, but not nearly at the level where this would have come up.)

@ilkkachu Yes, from what I remember, once a batch started to "resolve", i.e. its spells actually take effect, you couldn't add any more spells to it. (I too was a new player in those days and didn't fully understand it at the time.) FWIW here's a transcription of the early Magic rules which seems to back that up, see e.g. the section on page 19 about Instants.

@DavidZ, the text there is actually even weirder. Just under the page number 31, it talks about responding to direct damage with Unsummon: "You may choose whether the Unsummon comes before or after the damage spell, since you cast your spell last. Naturally, you choose to have it come first [to make the critter safe]." and also no mention of damage coming last as a rule: "If your rival had responded to your Unsummon with another damage-dealing spell, your rival could have opted to have that last spell take effect before your Unsummon, giving your creature the deep-six."

A really good answer! I must say that I was not aware of the fundamental difference between "batch" and "stack" ... also because, otherwise... youall at SE  could call yourself "Batch Exchange" rather!!! ... and my ignorance spilled over to the question, in which I ask what happens to damage that "goes on the stack", but referring to what happened at the time of the Alpha Edition,and referring to "batch" rather than "stack" ... anyway, doppelgreener he guessed right. Well, a really great job, it's a very clarifying question and answer!


text:
Where did Interrupts in Alpha & Beta Magic Editions end?
Here is another question regarding the very early Magic times, namely Alpha & Beta Edition.
The old rules for spellcasting worked with a “Batch”, described in the Fourth Edition rules booklet as:

A series of non-interrupt fast effects that build on one another as players respond to each other's spells.

I wonder then why it refers to "a series of non-interrupt fast effects", since it could happen that series of interrupts were also played, such as Counterspells, also one after the other, and with a method of resolution very similar to that of the instants.
The only difference, then, if I'm remembering well, was that interrupts had to be resolved between themselves first, and before every other fast effects; and only then, you had to check the instant and other fast effects, even if the fast effects would had cast after the interrupt.
So, the question is this:
Where did interrupts go , if they were not going on the batch?
In addition to what I have already reported, did the "batch" rule carry other consequences regarding interruptions?
Or is that all?
(that is, repeating myself: the interruptions must be resolved first, and regardless of all other fast effects)
Really thank you for tiny details provided ...!!

For the purposes of this question, let's look at current rules first. Right now you can divide a spell or ability life cycle into 2 parts: the announcement part, where you, among other things, pay costs, choose targets and so on; and later (hopefully) the resolution part, where the “effect” of the spell or ability happens. I'll call them announcement and resolution.
They need not come immediately one after the other. A spell or ability with “instant speed” can respond to another and thus happen completely “in between” the announcement and resolution of another spell, in the following timeline:

Announcement of spell 1
Announcement of ability 2
Resolution of ability 2
Resolution of spell 1

That's how “non-interrupt fast effects” also worked during the start of the game.
There is only one difference to today, and why the term “stack” was used starting with 6th Edition rules vs. the older “batch”. Nowadays more spells and abilities can be added to the stack after just one spell or ability resolves. That was not possible with the batch—once both players passed and declined to add more to the batch, it would wind down completely until nothing was left, and the active player could start a new one.
Alpha/Beta rules
Under the Alpha and Beta rules and up to before 6th edition, there was a third part of a spell or ability's life cycle: a window within which interrupts could mess with that spell or ability, giving us this life cycle:

Announcement of spell or ability
Interrupt window (use it before it closes)
Resolution

During the interrupt window, only interrupt spells (like Counterspell) or abilities that said they are “played as an interrupt” (like on Ring of Immortals) could be played one after another.
But these interrupts weren't put into the batch. They were simply played one after another outside it, modifying the batch without being meaningfully a part of it. They were basically their own thing, in their own kind of “sequence” off to the side.
The tricky part, of course, was that interrupts are themselves spells (or abilities), so could be interrupted as well, in their own interrupt window. The other player would have an opportunity to interrupt, or pass and let interrupts resolve.
So a small "Counterspell war" in Alpha/Beta might have gone like this, with parts by the active player playing spell 1 and Counterspell B, while the other player plays Counterspell A

Announcement of spell 1
Interrupt window of spell 1

Announcement of Counterspell A targeting spell 1
Interrupt window of Counterspell A

Announcement of Counterpsell B targeting Countrerspell A
Interrupt window of Counterspell B: nothing played
Resolution of Counterspell B: counters counterspell A

(Counterspell A never resolves, because it was countered.)

Resolution of spell 1

If you think this is needlessly complicated, you have a good point.
There was an idea behind it all though: Interrupts either added mana or responded to spells. Responding to spells was considered to need a “faster” speed than instant because it didn't just somehow counteract a spell (like a Giant Growth might counteract a Lightning Bolt without actually influencing the Lighning Bolt itself), but it actually "deleted" a spell (Counterspell) or modified it (make it green with Lifelace).
Under the Alpha/Beta rules, once a spell's interrupt window was over and it had “survived”, you knew it would resolve (where it might still “fizzle” for having no valid target). Once the interrupt window was over, the game would consider that the spell was “cast” or “successfully cast”. This was a trigger condition for some effects, like on Wooden Sphere where you could pay 1 generic mana to gain 1 life for a successfully cast green spell.
This means that if you had a Wooden Sphere and your green spell was countered, you couldn't gain life from the Sphere. Under current rules you do, because the trigger condition just happens immediatley after the spell is cast.
Sixth edition developments
The rules team was overhauling the rules continuously from one core set to the next, often introducing new systems in the expansions in between. It was realized between the development of 5th Edition and 6th Edition that cards like Counterspell could exist as instants with not many differences in behaviour.
So 6th Edition rules got a major overhaul of the timing rules and introduced the stack, plus damage on the stack for combat, to many complaints of players who saw the game continuously being dumbed down and intricancies being removed for "the dumb masses" that were supposedly the new target of Wizards.
In reality, when I look from time to time at some Magic questions here, having left the Magic playing community some 20 years ago, there have been so many other kinds of effects, card types and game modes added that streamling some timing things was the right thing to do, in my opinion.
It's better to have a common timing system like the stack that has relatively low complexity and then put the complexity into the cards, than have a complex dual system with batches for non-interrupts and just a "sequence" for interrupts.

@doppelgreener: Thanks for the edits to make it more readable/better understandable.

A great response from @Ingix.However,there is still a small doubt (in my opinion,but it may be that it was just my interpretation),which in fact is asked in the question"Is it possible to target spells placed at the bottom of a just-cast fast-effects chain?",to which I refer hoping for an answer.Is it possible(or not),to cast an instant after an interrupt has been cast,but without the whole batch being resolved?In my opinion it should be possible:in fact,why to say that interrupts should be resolved first,if it were not possible to continue the chain of spells by casting additional instants?

In Alpha/Beta that was possible, that changed with 5th edition rules, which was the first "try" to get interrupts reorganized: https://mtg.fandom.com/wiki/Fifth_Edition/Rules_changes
See the "interrupt timing" section there.

Thanks @Ingix ! So, if you have the time to do so, please, why don't you also try to answer the question regarding the practical example of a situation similar to the one posed here ("Was it possible to target spells placed at the bottom of a just-cast fast-effects chain?")?. I thank you, in any case.

Wizards have been kind enough to make available the transcript of a rulebook from the first era of Magic here. Among other things, it details the card types.

Instants: An instant can be played at any time, and is always discarded afterwards. You cannot interrupt your rival with an instant, but your rival's spells do not take effect until after you have had a chance to respond with instants and other fast effects. Once you have responded, your rival can respond to you, and so forth. After all responses are finished, all spells take place at the same time.
Interrupts: Interrupts can be played by either player at any time. Many interrupts modify the effects of spells; you cast them just as you or your rival are playing a spell you want to change. Although you must discard the interrupt immediately after you play it, its modification to a spell such as a summoning can be permanent. If you are not sure if you want to cast an interrupt, ask your rival to wait while you think. After your rival casts another spell, it is too late to interrupt the first. You may interrupt your own spells, and you and your rival can play more than one interrupt at a time. If you interrupt your own spells, your interrupt happens before your rival's. You may also interrupt an interrupt.

So the way I read this, interrupts were played during the casting of another spell (probably comparable to where we now have an opportunity to activate mana abilities to pay for spells), immediately took effect, then went into the graveyard. All the while a player is still in the middle of casting something, like an instant, or another interrupt, or activating an ability. The interrupts were never placed on the batch.
Mark Rosewater himself has said the Split Second mechanic from Time Stop is reminiscent of how interrupts worked back in the day (see for instance footnote 24 in this rant), and that rhymes well with what I see here, apart from the ability to interrupt interrupts (I guess Split Second could have allowed other Split Second cards to be played while they are on the stack, but that seems finicky).


text:
In "Super Cluedo Challenge", how should the removal rule be applied properly?

In "Super Cluedo Challenge", the instruction booklet I have in my possession explains, in an ambiguous way (in my opinion), the important rule of the "removal".
To better clarify which game I am talking about, it is good to say that it is the version of Cluedo that includes nine different characters (which is also the maximum number of players who can take part in the investigations), and in which there are three containers (black, green, ivory) in which to put the cards of the final solution.
Here we talk about the rule activated when a player ends up in a square adjacent to that of another player.
The booklet in my possession reads verbatim:

If a player ends his move by arriving in a room on a square adjacent to that of another player, he has two possibilities, namely:

leave the statuettes as they are; or,

move the statuette of the opposing player to any other space on the board ...".

And then, a little further on, the booklet goes on to say:

"If the player who enters the room ends up on a square adjacent to more than one (two) statuettes, he moves only one of his choice".

(emphasis mine)
And then the question is:
Is this rule activated only inside the rooms, and, in particular, is it activated only if a player enters a room on that turn, or is it activated every time you end up close to an opponent, but inside rooms only? (this means this rule isn't activated in the garden, for example).
Everything takes on a particular value when you find yourself (and obviously the other players too) having to find clues in the garden (in the flowerbed, in the fountain, etc ...).
In fact, since you are not inside a room, the removal rule should not apply.
But in those cases it often happens that a player gets "wedged" between two others, since there is a narrow corridor, and you cannot pass.
So, it would seem that the solution is precisely to "remove" a player even outside the rooms.
But this is precisely the question I ask:
In your opinion and experience,is the removal rule applied in rooms only, or is the wording wrong, and this rule also applies in the gardens (for example)?
Thank you all for the attention.

What I tend to say with this question is that, in my opinion, it would be appropriate to introduce the rule of the "removal" also outside the rooms, especially in the gardens. Or, a way should be proposed to solve the problem of the "entanglement" that occurs in gardens. One way to solve the problem could be to make an exception - to the rule that a player cannot "jump" an opponent's statuette - when it is impossible to do otherwise, ie when a player cannot legally move his statuette.

Can you provide pictures of the instruction booklet where it says these rules?

I have got an Italian instruction booklet only, which literally says what I reported in the OP. It is currently impossible to scan it in a sufficiently visible form, since it dates back to 1988. Why expect irrefutable evidence? You are great , DenisS. Anyway, sometimes you  are also a person who trusts others too little... You always like too much to play at being a modern St. Thomas, who "wants to verify for himself" everything that happens ... it is not necessarily a good attitude. Sometimes you should trust your neighbor more, it would do you good. Anyway, thanks for your concern!

I attempted to scan and send an image of the booklet. But it comes larger than 2 MiB (the limit allowed by Stack exchange). I also tried to turn it into pdf, but it doesn't take it anyway. Could anyone tell me Is there an alternative way to send this image file? Should I use the "Browse" option correctly?

There may be some problem with the correct translation of this game in its official English version. It is about a game that was published  in Italy (1988),with the name "Super Cluedo" - that is, an alternative version of Clue, with the cards inserted in special containers, green, black, and ivory - and which some sites say is called "Clue Master Detective ". but perhaps it is simply called Super Cluedo, even in the US and UK

The reason why I'd like to see a scan of the rules is because I found what purports to be a reprint of the rules from the 1988 game and there is nothing in the rule book that says what your question asks.  https://winning-moves.com/images/ClueMstrDet_Rules.pdf

And actually there's the problem, this question is not about "Clue Master Detective" or "Super Cluedo" but about "Super Cluedo Challenge" cluedofan.com/sccrule.htm They're two seperate games

Yes, I'm having problems with the scan of the booklet, and with the english name of this game too. So, thank you @DenisS, I think "Super Cluedo Challenge" is the corect name of the english version of the game I'm talking about. Let me say this words, too, in the end... Excuse me, Murgatroid!!!

Anyway...at last, I did it!! here is the scannerized italian  instruction booklet! You can find it in the new edited question text. The rule to which I refer is the number 12 of the second page of the booklet (of the two that I have included in the application). Even if it is written in Italian (if you do not know how to understand it, you can use a translator by copying exactly the sentences indicated in rule 12). so,by  now, I hope the whole thing is quite more clear.

I can't comment so here is my answer:
I have the english version of this game, the rule in question is written as folows verbatim:

If a player finishes a move in a room on a space ADJACENT to one occupied by another player, the player entering the room can EITHER:-
i) Leave the Charachter pieces as they are OR - ii) Remove the other
charachter[sic] piece and place it ANYWHERE else on the board, EXCEPT on
the spaces occupied by :- another Charachter piece, a Weapon, a Garden
Ornament or a Clue Counter. If there is more than one player adjacent
then the player entering the room has the choice of moving EITHER
Charachter pieces as above, but NOT both.

Which I think has the same ambiguity. I wonder if 'finishes a move in a room' and 'entering the room' is included in an attept to clear uncertainty around the meaning of an adjacent space. I think we are safe to assume spaces on either side of a wall would not be considered adjacent. But, is a space that is the other side of a french window an adjacent space? The space the other side of a door? The other end of a stair/secret passage? It could be thought that adjacent space here is not just one that a player could move into, as 'in a room' is an attempt to bound the definition of adjacent space to the immediate area. For example, your move finishes in the corridor next to a door, there is a player inside the door blocking the entrance to the room, you would not be able to move the player as you are not in the same room.
With this in mind I believe a strict interpretation of this rule as follows:

'the player entering the room' - indeed, the player must enter the room on that turn for the rule to become effective.

An 'adjacent space' is any space any player could legally move into from their current location ie. not through walls, or diagonal spaces.

'In a room', means the rule would not apply for an opponent's charachter piece on an adjacent space in another room. For example, to players either side of doorways, french windows or either end of stairs/secrect passages.

the garden is not a room, taking a dictionary meaning of 'room'.

However, I have also found the issue of 'blocking', particularly  when racing to garden ornaments, which is amplified with more players. For example, playing with 8 or 9 people, if the first or second player blocks the most convenient route, or ends up very close to or in the space adjacent to the target garden ornament there is little chance remaining players will win the race, this significantly holds up game play as they must all take a hopeless turn until the inevitable blocking player's turn which wins them the race.
As an idea to fix this possible flaw in the gameplay and make things as simple as possible, I would suggest the following alterations for this rule:

You do not need to have entered the room.
The rule applies everywhere, including the garden and corridors.
The rule applies to any 'adjacent space' (as above) including other sides of a door, french window and either end of stairs/secret passages.

With these changes, it will be possible to remove the blocking player in any situation if your move finishes next to them or both players are on a stair/secret passage. This will open up the race to all players and somewhat fix the slight flaw in the gameplay as 'blockers' could potentially be removed (you still need soemone to throw the right number to finish adjacent to them). A replacement rule could be worded:

If a player finishes a move on a space ADJACENT to one occupied
by another player, including spaces on either sides of doors, french windows and if both players are occupying stairs/secret passages, they can EITHER:-
i) Leave the Charachter pieces as they are OR -
ii) Remove the other Charachter piece and place it
ANYWHERE else on the board, EXCEPT on the spaces occupied by :-
another Charachter piece, a Weapon, a Garden Ornament or a Clue
Counter. If there is more than one adjacent Charachter piece then the
player can move only one Charachter piece, of their choice.

I have yet to try this adjustment to the rules but I will be suggesting it to my family for next time we play.

Thank you for your excellent response. I took some time to respond due to various personal problems, but after careful reading, I must say that I agree 100% with the proposed change of the  indicated rule. Again a big thank you and a greeting