I used to love the song "Blaze of Glory" by Bon Jovi. When the song was around I though the lyric "I have an old coat for a pillow" was "I have an old goat for a pillow". Now obviously I thought he couldn't use a goat that was alive as it would be standing up and wouldn't make a very comfortable pillow - so I always imagined Bon Jovi lying in the desert sleeping on the ground using a dead goat for a pillow!
A childhood belief about misheard lyrics

others believed things like this
- when I was little I believed that if I put a white stone under the pillow with my tooth I make more moneyAnon
- I used to believe in Perez mause when my teeth fall, I put them under the pillow to see what happened— AyrtonZ01
- My sister used to sing Kylie's "cheese on my pillow", somehow tears works better.— Tom
- My nephew refuses to put his tooth under his pillow in case the fairy burns him with her wand.— Nina
- When we were little my sister thought if you mixed cow’s milk and water you’d get goat’s milkAnon
- I used to believe that the lyrics to Bon Jovi's "You Give Love a Bad Name" were "You give love a Band-Aid".Anon