Okay, this is going to sound weird, but I used to believe that Queen's song "Bohemian Rhapsody" went: "Spare him his life in this monastary" not "Spare him his life from these monstrosities." I only found this out yesterday when I sang my lyrics at the top of my lungs, and I'm 22!
A childhood belief about misheard lyrics

others believed things like this
- In Queen's Bohemian Rhapsody, I used to think they were singing "Beelzebub has a devil for a sideboard!"Anon
- I used to believe that santa had a spare key to our house because we had no chimney.— Karl Andrade (Bombay, India)
- All through life, I always thought the lungs were located in your throat. I'm 25.— thelungs,man
- I used to believe that a life sentece was for when you stay in jail for your whole entire life.— Sara
- I used to believe that my life was a video game with only 1 life and that God was playing it. — Rina
- I used to think that the line in the song "Life in the Fast Lane" was "Fights in the Bat Plane".Anon