I know I'm not alone with this one:
No matter how many times I listen to "Help Me Rhonda," by the Beach Boys, I still hear the same strange phrase at the beginning:
"Well since she put me down, there's been owls pukin' in my bed."
I just looked up the lyrics and found out they're actually: "Well since she put me down I’ve been out doin’ in my head."
HUH?! That makes even less sense! I'm going to stick with my version.
A childhood belief about misheard lyrics

others believed things like this
- My mom said she had eyes in the back of her head. I looked and looked, but never found them.Anon
- I thought the lines in the sky left behind by airplanes were "sky scrapers". Makes sense.Anon
- I used to believe that God looked like an enormous version of "Woody" from the Toy Story series.— Ryan
- I used to hear "Everytime you go away, you take a piece of Meat with you"
Makes a nice light snack I spose.— Linda - I thought the lyrics to "We're going to Ibiza" by the Venga Boys was "We're going to eat pizza"— ShannonOfDoom
- I thought a major general is more powerful than just a general (which still kind of makes sense to me)— Demond