He looks like the fnaf 2 endoskeleton except it's head is twisted upside. He walks on 4 legs and all his feet are faceing in other directions. His back is covered with saws, drills, and hammers.
He starts in the Entrance Room, then the Elevator, then CAM X: Mickey's Clubhouse, then the Broadcasting Room, then the Phantoms fireplace, the Meat Freezer and then the office hanging from the ceiling.
He activates on Night 3 (Unofficial).
When he's hanging from the ceiling it is a reference to mangle from fnaf.
When he's in the elevator he doesn't instantly kill you.