Bonnie

The day, Bonnie appears as a friendly, harmless, joyful, nice, and sympathetic robot, who never harm children and always take care of them, often playing guitar along Freddy and the rest of the gang to distract customers of the restaurant; albeit his appearance is somewhat disturbing, and his behavior rather malevolent upon confronted to adults.

Once he is confronted to the night guard, Bonnie turns into a cunning, malicious, merciless, evil-minded, rather impatient murderous stalker, obsessed by the idea of stuffing the night guard into a spare animatronic suit for some dark reasons (presumably as revenge of the spirit within him).

Bonnie is by far the most active, being usually the first one to leave the stage, but also the least dangerous of the original five animatronics. If he waits outside the door, it isn't for very long, although even if he is far from the office, he can travel there surprisingly quickly. Shutting the door on him wears him out quickly into leaving, as opposed to the persistent Chica.

One of his dirtiest tactics is to hide in the storage closet, and bound to the office at an incredible speed, catching Mike off-guard.

He is very unpredictable and possibly impatient as he twitches constantly on Night 3, indicating he might be getting frustrated. Bonnie is, in fact, possessed by the soul of one of the children killed by William Afton, which explains his temperamental and evil behavior.