This page has secrets & easter eggs that have been found in Fazbear Entertainment.
Balloon Boy has a small chance to appear in your office when lowering the camera. While in your office, you cannot use the lights or doors, and he laughs continously. He leaves once you raise the camera again.
Mangle has a small chance to appear in your office when lowering the camera after not raising it for ~30 seconds. When you raise your camera, Mangle has a 1 in 5 chance to kill you.