I used to believe that there were barracudas under the docks at Chautauqua. (A counselor told me this when I was 5, to keep us from playing under the docks and being out of sight of the lifeguards.) To this day, I hesitate to go under a dock, and feel very uncomfortable there.
A childhood belief about monsters

others believed things like this
- I thought when a road sight said Dead End that someone had actually died there.Anon
- I was told as a kid that when it thundered, God was playing basket ball. LOL! — Tony
- When I was a child I used to believe that stand up pianos actually told jokes as well as playing music.— L MAN
- My dad told me that playing basketball makes you taller. Basketball players are tall, so I believed him.Anon
- My parents told me that when the ice cream van was playing music, it means he's run out of ice cream :(Anon
- when i was a kid my mother told me that when the ice cream man was playing his music he was out of ice cream— Lynnzea