At the end of FNAF 4, after beating Nightmare(Night 6)    you will be rewarded with a new minigame. in this  Minigame(FNaF4)  the FNAF 4 kid is being surrounded by his brothers in Fredbears family diner on his birthday. the brothers tease him, then carry him over to the stage and throw him into fredbears mouth.As we know, Fredbear was one of the original springlock suits that had malfunctioned and killed someone.and springlock suits snap whenever something touches the locks. In the minigame,the kid is crying all the way through so when he went in fredbears mouth his tears activated the springlocks and fredbears jaw went SNAP. This is the incident that Phone Guy mentions in FNAF 3 when he talks about springlocks.I call this The Bite Of 83 because if you listen closely to one of the phone calls from FNAF 3, Phone Guy mentions that the Springlock faliures happend In fredbears family dinner near 1983 and some other proof is that on theNight 1  minigame,when you wait in front of he tv, a Fredbear and friends show will come on, with the date 1983 on it. If this incident happened in 1983, it would perfectly line up with FNAF 2.