question: Why not use a 600lb goalie in hockey?
comment: The problem with this is that the goalies don't get to wear any larger pads if they are fat. Look at the pads the goalies already are wearing on their legs, it isn't likely you are going to get anyone who is able to take up any more space without recruiting an elephant. And if you did they would still need to block with their flesh which can't be pleasant. As others have mentioned the goalie will still need to move and that means your proposed fat goalie who's only distinguishing feature is taking up more space behind their pads isn't going to be able to block shots very well.
passages: The prohibition against goaltending was adopted by the NCAA in 1944 (and later by the NBL) specifically because of George Mikan. Prior to the advent of the high-jumping 6 ft 10 in (2.08 m) Mikan, goaltending was not addressed because it was thought physically impossible.
   Since about 2005, the Canadian Lacrosse Association has mandated one-piece unmodified chest protectors for all of its goalies. Because of the price, the team or the minor lacrosse organization often flips the bill for this costly piece of equipment. A legal upper should only stand out from the shoulders at any point by three inches and four inches on the arms.
  
  For pants, the box goalie generally wears hockey goalie pants or a specially modified version of hockey pants with airflow in mind.
  
  Section::::Equipment.:Other gear.
   Lacrosse leg guards or "irons" have taken a massive evolution since the early days of the sport. Early goaltenders wore cricket pads made from thin but rigid padding and a thick cloth material. Eventually these evolved into a cross between cricket and baseball catcher's leg guard. Like cricket, the irons covered high above the knee, while having an exoskeleton of molded plastic caps and shin plates to deflect shots and leave less or no bruising like in baseball. In the 2000s and 2010s, the size rules for these pads were very much tested as a market emerged for new lacrosse goalie equipment. Irons grew in width until it was arguable that they were no longer designed to protect the shin, but largely to cover more net. Eventually there was a push back, the Canadian Lacrosse Association and its partners set limitations on shin guard wideness.
   The National Hockey League (NHL) specifies maximum dimensions of goaltending equipment to prevent goaltenders from having an unfair advantage. Many other professional and non-professional leagues adhere to equipment size regulations based on International Ice Hockey Federation (IIHF) rules.
  
  Section::::Blocker.
   Section::::Chest and arm protector.
   The goals in box lacrosse are smaller than field lacrosse, traditionally wide and tall. Also, the goaltender wears much more protective padding, including a massive chest protector and armguard combination known as "uppers", large shin guards known as leg pads (both of which must follow strict measurement guidelines), and ice hockey-style goalie masks.
   At the minor level, most goalies have to wear throat guards or "cow catchers" that attach to the helmet to provide additional coverage for the throat and neck area.
  
  Section::::Equipment.:Leg guards.
   Section::::Catcher.
   Up until about 2005, the distribution and price of lacrosse style upper pads were extremely inhibitive. Until then, goaltenders generally engaged in "building up". Building up was a common practice, a goalie would buy a set of hockey uppers and add to them. Hockey uppers generally do not have enough padding to protect from downward shots or from up-bounces from bounce shots, so materials and other pieces of equipment were often added to protect from these, including: Football lineman shoulder pads, hockey shoulder pads, kidney guards, baseball belly guards, sectioned PVC piping (also used in old lacrosse slash guards), and thick cuts of foam. These augmentations were added not only to increase the upper body size of the goalie, but to increase their safety, comfort, but had to still maintain mobility.
   Box lacrosse goalies play in front of a four by four foot net at most levels, unlike a field goalie who plays in front of a six by six net. At the National Lacrosse League, Major, and Junior A levels a net four feet tall and four foot nine inches wide is used.
  
  Section::::Styles.
   BULLET::::- Stance: In a proper stance, the goaltender has the weight on the balls of his feet, the trapper and blocker just above knee-height and slightly out in front so they can be seen in the goalies peripheral vision, and the stick flat on the ice. Stance should also be conformed to the goaltender's style and comfort.
   BULLET::::- While playing for the Medicine Hat Tigers, Chris Osgood scored an empty-net goal; as well, Olaf Kolzig scored a goal while with the Tri-City Americans
  
  BULLET::::- April 20, 1993, Fred Brathwaite scored a goal while with the Detroit Jr. Red Wings
  
  BULLET::::- February 21, 1997, the Muskoka Bears' Ryan Venturelli became the first Metro Junior Hockey League goalie to score two goals (both empty net) in a hockey game. The goals came in an 11-6 win against the Durham Huskies
   Section::::Mask.
   BULLET::::- Goaltender jock: Due to the danger of bounce shots, lacrosse goaltenders generally wear an ice hockey goaltender's jock and cup for protection. Goaltender jocks offer more padding to the lower abdomen and genitals, while offering enough undercarriage protection to ward off most dangerous bounce shots.
  
  BULLET::::- Shoes: Most goalies wear typical running shoes. Goaltenders need the mobility to run and the grip to anchor themselves to the floor while in their stance, which can be provided by a good pair of shoes. Toe protection is generally not needed as the leg irons provide very long and wide foot guards.
   Section::::Equipment.
  
  A goaltender is required to wear certain protective gear. Every goaltender must wear gloves, a chest protector, a helmet, a throat guard, a mouth guard, and a protective cup. They optionally wear a padded girdle covering the waist to the thigh and elbow pads. Goaltenders' lacrosse stick is in between the length of the short and long sticks of field players. The head of the goalie's stick can be up to 12 inches at its widest point.
  
  Section::::Role.
   Today, most goaltenders utilize hybrid masks made of fiberglass, kevlar, carbon fiber, and other composite materials. Modern masks have a large cutout in the eye and nose area covered by a steel or titanium cage. 
   Section::::Stick.
   BULLET::::- November 12, 2012, Gabriel Grunwald (Wisconsin Badgers Alumni) of the OJHL Georgetown Raiders became the first goalie in history to score an empty-net shorthanded goal, while also posting a shutout in the exact same game. This game was played against the Mississauga Chargers.
  
  BULLET::::- April 8, 2013, George Sørensen of Denmark's national under-18 hockey team scored an empty-net shorthanded goal against France's national under-18 hockey team.
   BULLET::::- Goalkeepers (or netminders) use protective padding on the torso (plus shoulders) (the maximum amount is being regulated, since, as in ice hockey, many goalkeepers have been using massive protection to make them larger and broader), neck guard, large shin guards (not longer than 75 cm), gloves protecting the whole forearm and a helmet with either a grid or unbreakable transparent material. Unlike the Roller Hockey (Inline) Goalie who uses a Catch Glove to catch the shot on goal, the Roller hockey (Quad) Goalie uses a flat batting glove that provides rebound characteristics when blocking a shot on goal.
  
  Section::::Rules.
   In preparation for the playoffs, Plante was asked by Blake to remove it for a game on March 8, Plante donned the mask the next and for the remainder of his career. When he introduced the mask into the NHL, many questioned his dedication and bravery; in response, Plante made an analogy to a person skydiving without a parachute. Although Plante faced some laughter, the face-hugging fiberglass goaltender mask soon became the standard; by late 1969, only a few NHL goaltenders went 
   BULLET::::- Thomas Höneckl, December 21, 2012 (EC VSV vs HC TWK Innsbruck "Die Haie")
  
  Section::::Goaltenders credited with goals.:Australian Ice Hockey League (AIHL).
  
  BULLET::::- August 18, 2014: Melbourne Ice goaltender Jaden Pine-Murphy was credited with a shorthanded empty-net goal during a playoff game against the Newcastle North Stars.
  
  Section::::Goaltenders credited with goals.:Junior hockey.
  
  BULLET::::- January 7, 1987, Chris Clifford of the Kingston Canadians scored an empty-net goal against Toronto, becoming the first OHL goalie to score a goal
   BULLET::::- Goal pads – Perhaps the most visible part of a goalie's equipment, goalie "legs" are thickly padded, flat-faced leg pads covering the top of the skate, the player's shin and the knees, and incorporate additional padding on the inside of the leg and knee to protect the knee joint when dropping into a "butterfly". Pads are wide (recent NHL rule changes reduced the width of the pads) and sized to fit the individual player's legs. Most shots are blocked by some method of "pad stop".
   Neilson also discovered that if he put a defenceman in net instead of a goalie during a penalty shot, the defenceman could rush the attacker and greatly reduce the chances of a goal. Today the rule states that a team must use a goalie in net for a penalty shot, and that the goalie may not leave the crease until the attacking player touches the puck.
  
  Neilson was promoted for the 1976–77 season, coaching the Dallas Black Hawks in the former Central Hockey League.
  
  Section::::History.:Three seasons, three titles.
   Section::::Equipment.:Uppers and pants.
   BULLET::::- December 6, 2008, in two separate games, two different QMJHL goalies scored goals; Peter Delmas (Lewiston MAINEiacs) was credited with a goal against the Quebec Remparts and Maxim Gougeon (Rimouski Océanic) scored an empty-netter against the Cape Breton Screaming Eagles.
  
  BULLET::::- June 2009, during a junior B playoff game, Brantford Golden Eagles goaltender Daryl Borden scored an empty-netter.
  
  BULLET::::- April 23, 2012, Mark Visentin of the Niagara IceDogs scored an empty-net shorthanded goal during the playoffs against the Ottawa 67's.
  