I used to believe that sharks or alligators would come out of the vent in swimming pools. I would rarely go to the deep end and if I did, I would always check to see if something was coming out of the vent.
A childhood belief about monsters

others believed things like this
- I believe that there is a monster in the air vent and watches me when I put on my clothes— Blablabla
- I once thought a vent in my hotel room led down to the center of the earth.— flarn2006
- I used to believe that sharks lived under the pools where the air vents were. — Carol
- i used to believe that pools had underwater doors that sharks were going to swim out of.— marky
- I used to think that the pools was a swimming competition.— Matt
- my Dad told me ice rinks were defrosted every evening and turned into swimming pools— neil