I used to think that a "pool shark" was an actual shark that lived in a swimming pool
A childhood belief about swimming pools

others believed things like this
- When i was younger,I used to believe i could see a shark in a pool .Anon
- When I was a kid I used to think the "carpool lane" was an actual pool cars went swimming in— skeez
- I used to think that the TV show "Shark Tank" involved actual sharks in a tank.Anon
- I believed that the ladder on the back of a trailer/rv led up to a swimming pool.— marilese
- I used to believe that if you farted while swimming in the pool, it could propel you foward really fast.— Rick
- Up until I was in 3rd grade I believed my bathing cap is what kept me afloat in the swimming pool! Anon