When I was little, my older cousin told me that there was a "Potty Monster" that lived in the toilet and would grab your bum if you flushed the toilet while you were still sitting on it.
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 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 think people had a "potty mouth" if they had been drinking out of the toilet.Anon
- I used to believe that the toilet would suck me down if I flushed it.— :-)
- i use to believe that if i flushed the toilet when i was still on it would suck me down to who knows whereAnon