Prototype Attack

The "Prototype Attack" is an event that happened sometime before the events of Days in the Basement. It is an event in which a prototype animatronic attacked someone.

Information
It is known that it happened in a previous iteration of Fierce's Foods. Who performed it is unknown, however it is known it is a prototype. The prototype is said to be very glitchy.

Candidates
Here is a list of the candidates from the least likely to the most likely:

Wis is an extremely unlikely candidate, as he has no way to attack people. It is possible it could grab a person with it's three arm, but that wouldn't be enough to harm someone.

Orlockron is also unlikely as like Wis, he can't attack people. While he has no limbs, it has the ability to jump as a reasonable heigh, but despite this, it is very heavy which means it could've crushed someone.

Fierce has a jaw, but it doesn't haves any teeth. However, he has claws. Him doing the attack would explain why he was scrapped.

Richard is a possible perpetrator. He has a jaw with sharp teeth on it. He could also try grabbing someone with it's stubs.

Gilgamesh is the most likely candidate. He has actual hands which allows him to easily grab someone, constantly wields an axe and is the only character to actually kill the player in Several Nights at Fierce's.

It is possible it is an unknown animatronic who did the attack. It is unlikely it is any of the other animatronics as they are not prototypes.

Trivia

 * The prototype attack is extremely important to the lore. According to the creator, it is actually the cause of the series's events.
 * While The Doll is possibly a prototype, it is stuck to the ceiling and cannot grab the player which brings it out of the question.