Crazy Hand is a boss that appears with Master Hand in the games Super Smash Bros. Melee, and its sequel Super Smash Bros. Brawl, as well as Kirby & The Amazing Mirror. He looks very similar to Master Hand, although Master Hand is generally the calmer, more collected one, while Crazy Hand's fingers move in an erratic and frenzied way and will do anything to get the player off the platform. His bio in Super Smash Bros. Melee also states that while Master Hand loves to create, Crazy Hand is impulsive and destructive, consumed with the hollow feeling that comes from destroying one's own creations. Also, since Master Hand is generally thought of as the right hand of the two, this makes Crazy Hand the sinister left hand. In Super Smash Bros. Melee, Crazy Hand appears twice in the game; when a player clears Classic Mode on Normal difficulty or higher in a certain amount of time, and on the 50th event match, "Final Destination Match", where he is fought paired with Master Hand. In Kirby & The Amazing Mirror, he is also paired with Master Hand as the bosses of the level "Candy Constellation".
Due to his nature as a boss, Crazy Hand is normally playable through hacking only. With Action Replay, Crazy Hand can only be effectively controlled with the fourth controller. Any attempt to control him with another controller (1, 2 or 3) will result in Crazy Hand not responding to button presses. Also, in the "Kanto - Pokémon Stadium" level in Melee, his name is displayed as "Crazyhand".