I used to think a lyric to the oldy but goody "Twisting the Night Away" by Sam Cooke was "He's dancing with the chicken slacks." The real lyric is "He's dancing with the Chick In Slacks." For the longest time, I wondered what the heck chicken slacks were!
A childhood belief about misheard lyrics

others believed things like this
- I always wondered why shepherds washed their socks by night. (correct lyric: watched their flocks)— MaggieNJ
- I used to believe that if you buried a chicken bone in the backyard it would grow a chickenAnon
- When I caught chicken pox, I thought it was down to me eating too much chicken.— Helen
- I used to believe that all meats were chicken. I called everything chicken. :)— Girlfloyd
- I thought that eating chicken gave me muscles (chicken and muscles sound the same in Mandarin).— NG
- I used to believe when you had chicken pox, you turned into a chicken— Shirley