What is a "monster knight"? I was watching an agadmator video explaining a game between two chess engines, and at one point in the video after a knight move, agadmator talks about how that knight then became "basically a monster knight", and therefore must be taken. He then talks more about some other games involving "monster knights", but never really explains what he means by "monster knight".

My common sense is telling me that a "monster knight" is simply a knight that is well positioned, but from the way that agadmator talked about the concept, it seemed to me like there is a more precise definition of what makes a "monster knight". I googled around for a definition and didn't find it anywhere, hence why I am asking it here.

So, what's a "monster knight"?
The concept of a knight which is so powerfully placed (generally on e6/e3) that the game wins itself dates, according to Winter, from: 


  An observation by Zukertort after 26 Ne6 in the simultaneous game
  Steinitz v Maas, London, 5 November 1873:
  
  ‘The appearance of the knight at K6 [e6 for white, e3 for black] is generally, for the opponent,
  the proper signal to strike his colours.’
  Source: City of London Chess Magazine, May 1874, pages 97-98


Here is the game extract:

[title "Steinitz v Maas, London, 5 November 1873"]
[fen "3q1rk1/1rb3pp/b2p1p2/n2P1N2/1p1NP3/2p1B3/P4PPP/1Bn1Q1RK w - - 0 1"]

1. Ne6 Qe8 2. Bxc1 Rf7 3. g4 Qa4 4. g5 c2 5. gxf6 cxb1=Q 6. Nh6+ Kh8 7. Nxf7+ Kg8 8. Rxg7++


More from Winter:


  When the game Steinitz v von Bardeleben, Hastings, 1895 was shown in a
  ‘Chess Movies’ article on page 336 of the November 1949 Chess Review,
  the following comment referred to 19 Ne6:
  
  ‘A knight at K6 is like a bone in the throat, says Steinitz.’
  
  For the same attribution, see I.A. Horowitz’s books How to Win in the
  Chess Openings (New York, 1951), page 44, and How to Win at Chess (New
  York, 1968), page 50, but where did Steinitz make the comment?
  
  From page 212 of the first volume of Kasparov’s Predecessors series,
  before 16 Ne6 in Lasker v Capablanca, St Petersburg, 1914:
  
  ‘... the knight at e6 will be like a bone in his throat!’