I must admit, the thing that traumatized me most as a child was not in fact a scary movie at all, but a television commercial that would never be considered scary now. You must look at this from the eyes of a sensitive five-year-old child. The commercial was for a nasal-spray type of decongestant. I do not remember the brand, as I never watched the commercial for that long.
Anyway, the congested person featured on the commercial had a giant nose in place of a head. (I found out years later that once they used said decongestant, they had a regular head again.) I have no idea why this scarred my fragile psyche so much at the time, but every time the commercial came on, I ran from our family room screaming "IT'S THE BIG NOSE!"
I was frightened by this commercial for years. Even now, 14 years later, the thought of someone with an abnormally large nose in place of a head scares me. This is a humiliating traumafession, but I had to get it off of my chest somehow.