 The character Ermac actually originated as a glitch from the  original Mortal Kombat arcade game. If you unlocked the secret  battle with Reptile, on rare occasions the game would experience a  glitch, resulting in Reptiles pallete changing from green to redish  orange, and his name text changing to "ER MAC" ("error macro").  After this was discovered by gamers, the producers decided to  officially make "Ermac" a character.