When I was a child I believed that the lyrics in the song My Bonny Is Over The Ocean actually read My Pony Is Over The Ocean. So I thought the song was actually about some horse on a boat far far away from home.
A childhood belief about misheard lyrics

others believed things like this
- I used to think that the song "My Bonnie Lies Over the Ocean" was really "My Body Lies Over the Ocean."Anon
- I believed that the yellowish foam by the ocean was dolphin pee because my dad told me Anon
- I only found out last year that a pony is not a baby horse.— Mescaline Frumblethond
- i believed that michelle gayle's sweetness song contained the lyrics shade in sheep shit!— andrew
- I remember being scared of the ocean for a while as a little kid. I thought lobsters would pinch my toes.— Flipper
- I used to believe that somebody turned the ocean waves off at night.— David