The Man Upstairs is one of the best babysitter cautionary tales. The parents want a quiet evening out away from the children and hire a teenaged babysitter. When she arrives, they tell her the kids are sleeping and not to disturb them. Seems like an easy gig. The babysitter and call her friends, study her books, get a snack. Only, someone keeps calling her and baiting her with silence. Unnerved at being home alone in a strange place, she checks the doors and windows.
Then, the caller asks her, "have you checked the children?" Unsettled, she calls the restaurant where the parents are, but they are no longer there. Now, she's scared the phone will ring again. And, it does. The caller asks her again "why haven't you checked the children?"
Scared, she calls the police. They tell her that unless he's threatening her, there's nothing they can do, but they promise that if she keeps him on the line long enough, they will trace the call.
The phone rings again and she pleads with her tormenter to tell her what he wants, why he's doing this, trying desperately to keep him on the line. The caller hangs up. She wrings her hands and waits. The phone rings again.
Nervously, the babysitter picks it up and answers. It's the police. The officer warns her cautiously, "do not get excited, do not panic. We traced the call and it is coming from inside the house. Leave!"
She barely makes it out in time to land in the officer's arms. The police go in and find the children murdered in their beds.
I prefer the original 1970s movie version, "When a Stranger Calls," but I really loved the set for the newer version and it had some face to face confrontation with the killer which was pretty cool -