Mine and my friends theories on FNAF and FNAF2.

The Bite Of 87.

I asked you guys what you wanted first so we deliever. We will be doing all those theories but we'll do this one first. The bite of 87.

For some FNAF fans who are just getting into the game let me explain what this is. The bite of 87 is mentioned in FNAF 1 on your first night with the phone guy saying this exact dialogue: "They used to be allowed to walk around during the day to, but then there was the bite of 87. Yeah, its amazing how the human body can live without the frontal lobe, ya know?" That means that an animatronic violently bit someone which lead to them no longer having the frontal part of their brain. Most fans suspect Foxy to be the animatronic responsible for these reasons: Foxy has very sharp teeth and a large mouth which would cause serious damage, Foxy's jaw is broken, and three Foxy has been put "out of order" in FNAF 1. I already mentioned why I think Freddy and Toy Chica could've caused the bite but I have one more suspect which is the Mangled.

Let me sort of explain this one. The Mangled is a broken animatronic where kids rip it apart and put it back together. On night 5 of FNAF 2 phone guy tells you to stay near the animatronics and make sure no one gets hurt. It could be possible that Mangled was the one who caused the bite for this reason: When you are attacked by Mangled she lunges from above right where your frontal lobe would be. Some people think that the Mangled did this as a sort of suicide attempt which actually would make sense. Just think about it. Mangled has been torn apart by kids all its life. Maybe it was trying to get itself scrapped so it wouldn't have to suffer.