My husband told me once that when he was a kid he misunderstood a line from the Fleetwood Mac song "Second Hand News".
Real lyrics: I'm just second hand news...
He thought it was: I'm just standing here nude
When my son was small he thought BTO was "taking care of biscuits" instead of "taking care of business."
A childhood belief about misheard lyrics

others believed things like this
- I used to think that when people were taking their contacts out that they were taking their eyeball out :) — Jen
- I used to think that the Huey Lewis and the News song "I Want a New Drug" went "I Want a New Truck".— Chloe
- I used to think that my right hand wasn't my right hand anymore if I turned around.— Mike
- When I was small, my brother would bug me and say that if my hand was bigger than my head, I had a tumor.Anon
- when I was little, I was scared of taking the plane because I thought clods were solid !! — valentine a french student in eigth
- when I was little, I used to think that everyone was a child but someone invented adults to take care of us.— chocolate