Thanks to some movie, Ghoulies, I think it was. I believed that if you didn't get out of the bathroom before the toilet finished flushing that you would get sucked in. Or a monster would grab your rear if you didn't get off the toilet before it was done flushing.
A childhood belief about fear of

others believed things like this
- I used to believe that if you didn't close the toilet lid after flushing, you would get sucked down into it.— Maya
- I used to think if you didnt get up before flushing the toilet would eat you...Anon
- i used to think when it started raining it was god flushing the toilet— edel
- I was certain that rain was created by God having a pee and flushing his huge toilet above us— Emma H
- My best friend used to believe that when it rain and thundered that God was flushing his toilet. — Jelly Bean
- I used to believe the sound of a flushing toilet was nearly identical to the 90210 theme. — Laurenne