I used to believe that a killer whale lived in the deep end on my local swimming bath, but he didn't ever come out because he could only live in the deep part.
I also remember my mum talking about why she didn't like rodents because when she was small she picked up a gerbil by its tail when it was dead, and I thought she meant 'turtle' so for the longest time I thought that gerbils were a type of turtle.
A childhood belief about swimming pools

others believed things like this
- When I was a child i thought turtle wax, was to wax turtles.— J.P.
- I used to believe that pickles were hot dogs made from turtle meat.— Jerry Moe the Gimp
- Turtles can fly. I believed it for ages.
My turtle got lost or probably died and I was told it flew away.Anon - i used to think, when i was about 4 that i lived inside a whale because i live ion the country Wales— mike
- A common misheard lyric in BMTH’s ‘Shadow Moses’ is “THIS IS SANDPIT TURTLE!”— Oli
- I always believed that we lived in Manchester (we didn't) but it was always the main place on the local news!— Richard M