Cassidy is a young child killed by a man called William Afton and she possesses the animatronic called golden Freddy with Williams son Evan Afton who was killed by his brother Michael Afton by being shoved into the head of fredbear an animatronic William made and it crushed Evans skull and he possessed the old decaying version of it golden Freddy with Cassidy they are friends sometimes or others his being used as her toy/plaything whenever she decides to grow to a giantess size to have her fun.