When I was little, I used to think that when you flushed the toilet then if you didn't run away as fast as you possibly could and if you didn't close the door you would be eaten by a giant monster that lived in the toilet.
A childhood belief about fear of

others believed things like this
- I used to believe that monsters lived in my toilet and they ate my poop and urine when i flushed the toilet.Anon
- I used to believe that Limabeans would kill you if you didn't eat them.
I flushed them down the toilet.— Lima - 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 believe that if I flushed the toilet before I showered, I would take a shower in dirty toilet water.— Chris D
- I used to think if I left the toilet seat open my cat would get flushed down the toilet.— G
- I used to believe that the toilet would suck me down if I flushed it.— :-)