i remember an episode of Are You Afraid of the Dark where there was this nasty hairy slimey monster in a pool that drowned people, and from the time i saw it til i was about 13 i would never go to the middle of a pool no matter how deep it was for any reason. not even with a group of people.
A childhood belief about swimming pools

others believed things like this
- i used to believe there were invisible sharks in the deep end of the pool, thanks to my older brother.— Melissa
- I believed that the Kreepy Crawlie used to clean our pool, would follow me around the pool and eat me. — Mother-of-2
- I used to think that a "pool shark" was an actual shark that lived in a swimming poolAnon
- If you pee in a pool, the pee disappearsAnon
- I used to believe that your tap water came from the swimmimg pool.— Mimi
- When i was younger,I used to believe i could see a shark in a pool .Anon