Mad Piano is an enemy appearing in Big Boo's Haunt.
When not attacking, Mad Piano is stationary in its original position. When Mario is within 500 units of the Mad Piano, after 20 frames if Mario is moving forward Mad Piano attacks and becomes tangible. When Mad Piano attacks, it moves forward at 5 units per frame while turning toward Mario. If Mario moves more than 500 units from the Piano, a timer begins. If Mario does not move back into the 500 unit radius within 80 frames, when Mad Piano's attack animation ends it goes back to being stationary.