A childhood belief about fear of

In the boy's toilets at our primary school, there used to be 5 cubicles, however one of them never opened. For years everyone thought that a pupil had fallen down the toilet and the cubicle had been sealed. None of the teachers knew we thought this. Anyway, one parent's evening (student-teacher conference) someone's father was desperate to use the toilet so he just opened the door to the forbidden cubicle and walked in. Needless to say there was mass hysteria from the boy in the toilet, who all came screaming out. Turns out that the door had just been stuck with bubble gum. I also later found out that the teachers knew about it, but never told because they liked the idea of an emergency staff toilet that was always free and CLEAN!