The Spider Mastermind or Spiderdemon is one of the boss enemies in Doom, appearing in the last level of both the third and the fourth episode; it is also the second toughest creature in the series, owing to its 3000 HP which places it right after the Cyberdemon. The Mastermind can be described as a large brain with two red eyes and a mouth filled with sharp teeth, attached to a metal platform with four mechanical legs which also serves as housing for a powerful super-chaingun. The Arachnotrons in Doom II and Final Doom appear as a smaller version of the Spider Mastermind and are, according to the Doom II manual, its offspring. Its reliance on a bullet firing weapon makes the Mastermind capable of engaging into monster infighting both with other creatures and its own similars. Notably, MAP20 - "Gotcha!" in Doom II revolves around the possibility for the player to trick a Spider Mastermind and a Cyberdemon into fighting each other.