Most people think of TV movies as cheesy, inferior versions of their big-screen counterparts, but no other movie has caused as much fear in its viewers as the BBC film Ghostwatch.
The movie was shown on Halloween in 1992 and purported itself to be a real, live, on-air investigation of a haunted house, starting off the segment with the following script:
"The program you are about to watch is a unique live investigation of the supernatural. It contains material which some viewers might find disturbing."
If you thought people reacted badly to The Blair Witch Project when people still believed it was a true story, just imagine how psychologically traumatizing Ghostwatch had to be in order to cause post traumatic stress disorder in some of the movie's younger viewers.
Interestingly, the film ended up having long-reaching effects in psychology, even instigating a proposed change for the definition of PTSD to specifically exclude exposure to traumatic events through electronic media.