His actual name is William Afton. But he is in the spring bonnie suit. He lies and manipulates kids to kill them, he is in a spring lock suits, spring lock suits are flimsy but have mechanisms to switch from a suit to an animatronic. Except if it fails and switches to animatronic mode while someone is inside, then tons of metals screws and other pieces of metal to hold the animatronic together will all at once snap into place which will crush and impale the person inside, a springlock failure