The Mad Piano is a piano enemy in Super Mario 64 and its remake for the DS, Super Mario 64 DS. It is a large grand piano that opens its mouth and begins to attack the player if they approach it. It is invulnerable, and like other invulnerable enemies, it takes up three of the player's eight lives. Mad Pianos make their only appearance in Big Boo's Haunt, the fifth main course of the game, in Super Mario 64.
When he enters his final phase, the boss Amadeus Wolfgeist will possess the piano. This turns him into another Mad Piano.