A friend of mine used to think that the Scribe song that is supposed to go "How many dudes you know flow like this? Not many, if any" was "How many dudes you know flow like this? How many, bout fity" (as in, slang of fifty!)
A childhood belief about misheard lyrics

others believed things like this
- My friend's sister believed the lyrics to Gazza's "Fog on the Tyne" were "Fog on the dinasaurs mine all mine"— Suzanne
- i used to think that if i tore a dollar bill in half it would make fifty cents— stacy
- I used to think Cockneys only ever talked in rhyming slang.Anon
- "Chassis" is slang for a woman's body, especially her genitalia.
— Siddharth Mehrotra - For whatever reason, I thought that grass was slang for tobacco rather than marijuana.Anon
- A friend of mine seemed to think that 100 pence was worth £6.— Richard Davies