I used to believe a drain monster would come out of the toilet every time I flushed, or walked over sewer grates.
A childhood belief about monsters

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 believe that people were buried in "grates".— Grate Job
- 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