When I was about 13, I watched way too many horror movies, and for some reason I used to think that Jason fron the Friday the 13th movies, Michael Myers from the Halloween series, and Alfred Hitchcock were hiding in my room and would "get" me if I didn't turn on the light when I went in. This was made worse by the fact that I didn't have an overhead light in my room and had to walk all the way over to the lamp next to my bed and would close my eyes until I turned it on, convinced that they couldn't get me if I couldn't see them.
For some reason, I was never scared of Freddy Krueger.
A childhood belief about under my bed

others believed things like this
- My dad told me that the reason Birds didn't get electrocuted on overhead wire was they had rubber feet!!— Derricki
- When I was a child I used to believe that movies and series were real.Anon
- I used to believe that what happened in science fiction/horror is movies was realAnon
- I used to turn the TV off when I left the room so I didn't miss anything.— S.Lee
- I used to believe that Mike Meyers and Michael Myers where the same person— RS
- i believed that if you farted too much in a room and you were to light a flame your house would blow up— the nuclear fart