The bite of '87, also referred to as the bite of Fredbear is a major incident which eventually led to Kenny Johnson's death.
The bite happened July 23rd of 1987 at Fredbear's Family Diner, on the day of Kenny's birthday. It was shown in Part 189, caused after his brother, Richard Valley and Jackson shoved him into the mouth of one of restaurant's animatronics, Fredbear, causing Kenny's skull to be crushed. The damage only got worse after one of the employees tried to pull him out in Part 190.
Kenny survived the bite, however, it caused him to land in a hospital, where his frontal lobe was removed, as shown in Part 191. He would've most likely lived if Samuel White hadn't turned off his life support, as implied by Part 196.
The bite was later mentioned by Samuel in Part 208 .