10 Horror Movie Moments Everyone Was Waiting For (That Never Happened)

In Black Christmas, Jess and her sorority sisters are having a party, when they receive an obscene phone call from someone called Billy. At first, the teens assumed the caller is a random prankster. But after people in the house and the neighbourhood wound up dead, Jess realises Billy is a serial killer.

Because Jess' partner, Peter, disappears when these phone calls happen, it's heavily implied he is "Billy". This theory is validated further when Jess discovers the phone calls are being made in the house, meaning the killer has been among Jess and her friends the whole time.

Concluding her boyfriend must be the killer, Jess strikes Peter with a fire poker, killing him. As the police put Jess to bed, it seems like the story is ready to wrap up. But in the film's closing moments, we hear a voice from the attic, proving Billy is still there.

Although viewers naturally expected some big twist about Billy's true identity, it never happens. We never learn who he is, why he lives in this house, or why he preyed on these women. Apart from a single shot of his eye, we never see what he looks like.