Mad Piano

The Mad Piano is a piano appearing in Super Mario 64 and Super Mario 64 DS. It looks normal at first, but when the player approaches the instrument, it begins to open and close its lid, revealing sharp teeth. The Mad Piano then proceeds to chase and attack them (while making the sounds that sound like someone hitting its keys) until they are far enough away. The Mad Piano appears only in Big Boo's Haunt and protects a Red Coin found behind it.

It is impossible to defeat this enemy in any way, despite the Nintendo Power Player's Guide erroneously stating otherwise.

A similar piano makes a cameo appearance in Mario Party 2 in Horror Land at night.

Another similar piano appears in Mario Party 8 in the board King Boo's Haunted Hideaway.

What appears to be the Mad Piano makes a cameo on a poster in the Last Resort hotel in Luigi's Mansion 3.