My younger sister used to have a teddy bear named "Bim-Bim" She thought the song "Taking Care of Business" was "Taking Care of Bim-Bim" My parents played along so well, that I believed (I was 8-10 at the time) that BTO had really written a song about my little sister's teddy bear.
A childhood belief about misheard lyrics

others believed things like this
- I used to talk with my teddy bear and I really thought he answered me.— Joy
- i used to believe that the factories were care bear factories because of the clouds of smogAnon
- when I was little my uncle told me he was part bear. I believed people could be part bear until I was twelve. — Audrey
- I'm autistic, and I used to believe taking some of my sister's food while she was eating it was sharing.Anon
- I used to think that when people were taking their contacts out that they were taking their eyeball out :) — Jen
- When I was a child I used to believe that teddy bears could talk to me at night.— Daiana