I don't know if it is a belief but I remember when I first learned to use the "potty" that I imagined that the waste would be cartoon characters. Like a pooh in a top hat type of thing, and that these cartoon droppings were all collected in some place where they could go have a party.
A childhood belief about general

others believed things like this
- I thought cartoons were real, I remember asking my mom why there were lines around the "actors" in a cartoon.— Steven Graziano
- I had alligators and cartoon lions under my bed.— ruth
- Before the invention of the camera, everything looked like a cartoon with the quality/effect of oil painting.— MD Caruso
- i used to picture jesus as a kind of cartoon Tarzan, swinging through the trees...— bex
- I loved watching the cartoon Casper the Friendly Ghost and wondered why the Holy Ghost never got his own show.— Robert
- I used to think an evil spirit type thing called Wango lived in my dog. I was terrified of that dog.— Franklin