I used to think that a carpool was one of those bug, long limosine's with a pool all the way in the back.
A childhood belief about swimming pools

others believed things like this
- When I was a kid I used to think the "carpool lane" was an actual pool cars went swimming in— skeez
- Whenever my fingers wrinkled from staying in the pool too long, I thought I was aging faster.— The Mortal Elf
- I believed that the ladder on the back of a trailer/rv led up to a swimming pool.— marilese
- 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