In Tim McGraw's song "Back When" my sister used to think it said, "don't you remember the piss in a pepper", not "fizz in a pepper". She couldn't understand why they would play that word on the radio!
Also, the Jimmy Buffet song "Fins" was confusing to my mother... she used to sing "Dance to the left, Dance to the right" when of course the phrase is "Fins to the left, fins to the right". I loe to make fun of her about this but she comes back with some of my own mistakes, which I will never admit here.
A childhood belief about misheard lyrics

others believed things like this
- I believed Dr. Pepper was pepper-flavored medicine and was afraid to drink it.Anon
- I used to believe that Dr. Pepper actually tastes like Black pepper. I'm still afraid to try it.Anon
- I never used to understand why salt was bad for you, but pepper wasn't.— Lara
- I used to think that when a song finished on the radio it would play again on the next station— Maria
- Does anybody remember that song "OUT OF REACH" well i remember i used to sing it as "BATTEERRRRYYY". — meeeeeeeee
- I used to think that pepper was only used to mark where you'd put the salt.— BK