When I was 12 in the early 90s it was customary to have sleepovers and watch deeply inappropriate films.
There was one I remember being so utterly terrifying but don't know the name. For some reason I want to find it and watch it again to see if it was as bad as I remember.
I'm afraid the details are somewhat hazy: all I remember was it was a bit a train with a murderer on it (it might have been in black and white but I am not sure)
You never saw the murderers face, just saw him going up and down the carriages.
Years later I watched the German silent film "M" and it made me think of it if that is in any way obscurely helpful.