When I had nightmares, I was afraid to go to the toilet - because I meant the monster/evil thing was in there. I meant it would drag me down and drown me.
I was afraid of the nightmares in a couple of days, before I forgot them. It was scary!
A childhood belief about fear of

others believed things like this
- for years i was afraid to throw up because i thought it meant i was possessed like in the exorcist.Anon
- I used to think that gummy bears were evil and wanted to take over the world. I'm afraid of them to this day.Anon
- I used to be afraid of Tina Turner. I saw her as a monster or something like that.— Kinha SP
- eating cheese before bed gives you nightmaresAnon
- I used to believe that a dream catcher really made nightmares go away.
— WOLVERINEfLASH14 - I used to believe that eating chicken skin will give me nightmares.— zihui