When I was young I used to believe that the ticking of my clock would draw Captain Hook to my room, where he would assault me with his hook.
Another Captain Hook story: when I was at Disneyland as a small child, I used to think that Captain Hook's sword was real, so when I met him, I tried to pull out his sword. Upon failing, I thought he was really mad at me.
A childhood belief about monsters

others believed things like this
- That captain hook lived in my closet on the very top shelf.Anon
- I used to think God was Captain Planet.Anon
- I used to believe that the Captain's Log in Star Trek, was really a log— Anna
- I was a superhero named Captain Stupid.— Chr1s
- I used to think that when a movie was 'based on a true story' it was happening for real then and there— Tom
- When I was little I wanted to go to Disneyland as soon as I could, before Mickey Mouse died.— Mary