As a child I guess I had no conception of conservation of matter, and thought it certainly didn't apply to pooping. I thought that pooping was a matter of your body creating something out of nothing, and that it could go on indefinitely. I had nightmares in which I was uncontrolably pooing over a long period of time, unable to stop until I despired of any hope that I wouldn't go on to fill the entire universe with shit. And for a long time I lived in mortal fear that just such a thing was entirely possible in real life.
A childhood belief about weeing and pooing

others believed things like this
- I thought the mole on my arm was from a bug pooping on my arm a long time agoAnon
- My brother used to be scared to poop in the potty. He thought that he was pooping out his bones.— Lillyth
- I used to believe that if you left crumbs out for a long period of time, they would turn into ants.— Bylaberrie
- i used to think that when i was pooping a crocodile could come out of the toilet and bite my butt off.— derek
- I used to believe that, no matter what language other people spoke, that everyone thought in EnglishAnon
- I thought Viagra was an allergy medicine for a really long time.Anon