Unknown is one of the strange animatronics of the pizzeria, Unknown was supposed to be the animatronic to take place in the game area but it was too scary so he was thrown away in the darkest corner of the Parts and Service, where he met Freddy, Bonnie, Chica and Foxy, he became friends with them and became part of the crew.
Unknown is a human-like animatronic, he has got three long metallic hairs, colored like a phantom animatronic and has black eyes with red pupils.
Normal: title says it all.
Raging: his eyes will glow red and his strength will be doubled, he's very aggressive on this mode and will attack anyone that annoys him.
Crazy: his eyes go fully white and his head starts twitching, he is capable to kill anyone that stands in his way.
1- When Unknown stares at the camera, theres a chance to see Unknown holding a sign that says "coming for ya".
2- Sometimes Unknown can appear in the office desk, sitting, looking down, and when you put on the Freddy mask, the lights will flicker and Unknown will start moving towards you and he will take off your mask and will disappear with your mask and the mask bar will not be seen, however, you can still use your mask, this easter egg is more of an hallucination.