FNaF game therioes

Bite of 87' theory

Theory # 1: I think that Mangle did it because she likes to attack from the ceiling giving her the perfect aim for the frontal lobe. Some proof for that is her attack position and because of her broken jaw. The broken jaw played a part in this because the frontal lobe is a big piece of the brain so she would have to break through the skull and brain to bite it off leaving her jaw broken. Also she is one of the only animatronics that can fit that big piece of frontal lobe in her mouth and bite it off. Also she is a newer model so she will most likely have a strong enough jaw to bite through the skull and bite off the frontal lobe.

Theory #2 Maybe Golden Fred bear did it because in FNaF 4 mini game the little boy you play as gets his head shoved by his older brother and friends into the mouth of the animatronic. He was crying his heart out so it dampened the spring locks causing them to snap shut. All that weight would definitely penetrate the skull and bite off the frontal lobe.

Theory #3 Maybe Foxy did it because he is similar to Mangle and has a large jaw, big enough to fit the frontal lobe. Foxy might have caused it and been put out of order for it but would his jaws be strong enough to bite off the frontal lobe? Plus his FNaF 1 jump scare is just him coming in but after you black out and the game is over he could have came over and bitten off your frontal lobe but that would be unnecessary to do. But, your head might have been too big and large to be stuffed into the suit so Foxy or another animatronic bit it off and then stuffed you into a suit but that is very unlikely because the police would have had to see the dead body to conclude that there was a missing frontal lobe on the victim of the bite of 87' and no body's in the animatronics where ever found out. But FNaF 2 Withered Foxy could have done it because he lunges  at you for his jump scare and maybe he ends up biting your frontal lobe off after hurling himself at you. But would Withered Foxy have strong enough jaws to break the skull? Who knows these are only theory's!