Scott Cawthon, the game's creator, stated that during development, he had nightmares about the character of Bonnie.
Bonnie was the first animatronic in the game
Scott Cawthon did modeling work on Foxy while on a bumpy car trip. Cawthon stated later he feels this is why Foxy ends up very broken in appearance.
The "phone guy" is voiced by the creator of the game, Scott Cawthon.
Scott Cawthon thought the extreme 20/20/20/20 AI customization would be impossible to beat, however a YouTuber named BigBugz managed to do it. Also, a YouTuber named Markiplier has a video explaining how to beat 20/20/20/20 mode.