I used to think that your knee cap was called your knee ball.
A childhood belief about general

others believed things like this
- When I was a little kid and fell down and skin my knee, I used to think I was skinning my kidney.— G. Dedrick
- I used to think volleyball was actually called "ball-y ball"Anon
- I was told as a kid that when it thundered, God was playing basket ball. LOL! — Tony
- I used to believe that your brain was a red rubber ball inside your head.— Greg
- I used to belive that the New Years ball exploded, and people who were near it died.— Angela
- I used to believe that eye-lash curlers were eye-ball eating aliens in disguise— Eliza