Cassidy is one of the victims of William Afton, and the soul within Golden Freddy (In game). However, in the Novel Trilogy, she possesses Bonnie instead.

Cassidy is the spirit possessing Golden Freddy, she were the first dead kid to possess an animatronic and is an important role through out the games of Five Nights at Freddy's.

(maybe make Cassidy again but in the movie version plz wait also no shiping C.C/Evan Afton with her it's weird & more like friends with her being a bit of a bully thx)