An episode of a long lost CITV British mini-series, titled The Frighteners. The episode was set in Victorian times I believe and centered on a little girl finding fairies at the bottom of her garden. Gradually, the fairies turned evil and the episode ended with the fairy's distorted face superimposed onto the mother (I think!) laughing maniacally. This episode aired in 1997. To this day, I have never been able to find it again, at the time I remember being extremely freaked out!!
The Witches film based on Roald Dahl's novel. We ended up watching it in primary school around Christmas time, where we watched videos as a treat before end of term. It freaked so many kids out, parents complained and it resulted in us being unable to watch PG rated films without parental consent from then on. I was terrified by the witch trying to coax the boy down from the tree house and of course all the scenes involving The Grand High Witch.
I remember seeing the scene from GHOSTWATCH out of context where the possessed voice was coming out of the girl's mouth. I watched it in full years later and it was truly a groundbreaking piece of television. It is understandable why it created so much hysteria at the time.
Lastly, I recall being freaked out by a music video which to this day I have been unable to identify. It was late at night and I think my family had VH1 on the TV. The music video featured a female singer, it was quite a psychedelic video, the song was upbeat. I remember close ups of the singer, she'd do something freaky with her eyes as if she was staring into the TV, then it would freeze frame. I may have confused it with "Groove is in the Heart" but from memory the singer looked different. She was brunette with a bob haircut. I'm guessing the video would have been 80's or early 90's.