When I was learning how to use the toilet (ie: potty training), I firmly believed that if I was alone while I did a "number 2", the resulting loaf would jump back up and bite my ass.
A childhood belief about weeing and pooing

others believed things like this
- I used to think people had a "potty mouth" if they had been drinking out of the toilet.Anon
- when i was little i believed that your social security number was the number you were born on the earth — christine
- My great-grandfather firmly believed, and had me convinced, that SPAM was mouse meat. — texasblue
- I used to believe that if you jump in a toilet, they lead you to another dimension.— beep.
- I used to believe that if I sat on the toilet too long a snake would come up and bite me.— Cheesemonkey
- I used to believe that crocodiles lived in the toilet and would bite my butt when I had to go to the loo.— Oz