The Maddened Pipe Organ is a villain in Epic Mickey.
Before Mickey got into Wasteland, the ghosts where in a ballroom in Lonesome Manor until the Pipe Organ frightens them. He is all steamed up and needs to be calmed down.
When you go to the Ballroom, you meet the Pipe Organ there.
When you jump on the plate, he will tell you to play his song. You must jump on the notes and he'll give you the Play a Tune pin. Then, the steam is gone and you can rescue Jarvis and Stuffus, but you need to pay them E-Tickets to let them fight the Mad Doctor. If you take too long, you need to try again to play his song. When you return to the Lonesome Ghost, he'll give you Donald's Torso.
If you thin out his keys, he complains and if you thin out all the keys, he will get surprised. Now, he is very angry, you need to fight a pair of Tankers. Then, you can go fight the Mad Doctor now.