I used to believe that the song by Fatboy Slim that goes "Right about now, funk soul brother, check it out now, the funk soul brother" went "Right about now, funk short rubber, check it out now, the funk short rubber". I loved that song in like third grade and would sing it on the way home from swimming lessons, but could never figure out why Mom would laugh at me...
A childhood belief about misheard lyrics

others believed things like this
- Since the girls name Jackie is short for Jacqueline, I thought the boys name Jack was short for JackalAnon
- I had an 18 lb. cat who ate rubber bands, I used to believe she could bounce away if not careful.— Dawn
- I used to believe that your brain was a red rubber ball inside your head.— Greg
- I used to believe that if I swallow chewing gum, a rubber tree will grow on my head!— Farry Aprianto
- I used to believe that Electricity was chiped overseas in large thick rubber boxes on ships.Anon
- My dad told me that the reason Birds didn't get electrocuted on overhead wire was they had rubber feet!!— Derricki