I've been listening to Metallica since mid-eighties, and they have a song called The Four Horsemen on the album Kill'em all. The beginning of the chorus goes - I though for many years:
"Once in a dully mirror
never seem they're right"
The real deal is
"The horsemen are drawing nearer
On the leather steeds they ride"
Dont know why I didnt think more over that dully mirror...
A childhood belief about misheard lyrics

others believed things like this
- when i was young i used to believe that my image on a mirror would come to life if i broke the mirror.Anon
- I used to believe the Metallica song "Trapped Under Ice" said "I turned down the rice."— Erik Z.
- I used to think that if a mirror with me in it breaks, I break.Anon
- I used to believe that there was a person in the mirror who looked exactly like meAnon
- I used to believe that when you cracked a mirror your reflection would come and take over your body!— XxXAbbeyXxX
- I used to think that if I looked in a mirror for over 5 mins I would dissapere to Narnia!— Quako