Curate, connect, and discover
FNAF Theories?
Maybe: the bite of '87 victim was tearing apart Funtime Foxy(? I don't know if Mangle is Funtime Foxy. This theory I wrote a year ago but the theory itself I knew since years back.) and the repair folk got tired of fixing him so they just let the kid rip her apart, becoming Mangle, and Mangle finally snapped and took a big bite on the kid. Kid's Cove turned into some Mix-and-Match play area after the destruction of Mangle. The Mangle bit out their frontal lobe. Possibly survived... Someone can live without a frontal lobe. Ask Phone Guy. Or don't, because he's probably very dead!
Also: C.C.(The Crying Child, Michael Afton's younger brother) lost his frontal lobe to Fredbear, went into a coma, died from The Nightmares when he was in the coma. Died (possibly) on his sixth birthday. Or after. Depending on how long he's been in the coma, but the point is- he got severely injured on his birthday.
But then, there are some things on that the '87 bite victim was a security guard named Jeremy Fitzgerald, and lost his frontal love. He was moved to the day shift, and must have been doing something to Mangle, causing her to last out. Don't hurt Mangle! He did nothing wrong. FNAF has a thing for lost frontal lobes. FNAF Theories.
This is just my thoughts and theories that I heard about years ago, and stuck by them since.