The first time he came to the diner he got lost and locked in,

William found him in parts and service

William didn't kill him but instead gave him a springbonnie mask,

And then it was opening time

That night Sid put on the mask and after a few minutes started hearing a voice whisper in his ear, it was William's voice,

(Ok this is basically Vanessa ig lol)

Ok nvm Sid finds the mask in p&s

ALSO OSMSJSJAKXS LOOK