Music Man is a nonlethal, purely audio-based animatronic! While not the most difficult character in the game, he may be the most evil.

Throughout the night, Music Man will mimic the sound cues of other animatronics and play them at random. However, these fake sound cues will be slightly out of tune and followed by a record scratch to let you know that they're not genuine. Music Man's challenge comes entirely in how he'll make you second-guess every audio cue you hear. His library of fake sound cues includes the sound of Freddy laughing, Foxy running, Bonnie and Chica walking, all the vent animatronics approaching, et cetera.

While you probably won't get yourself killed if you get tricked into thinking his fake audio cues are real, you definitely will if you start thinking the other animatronics' real audio cues are fake. Be sure to stay alert when he's active - listen out for the slight differences in his cues to suss out which ones are the real deal!

(Normally this is where I'd include screenshots of the animatronic ingame, but because Music man is purely audio-based, you never actually SEE him in the office...so here's a screenshot of him in the salvage location instead!)