I had a friend who thought blackberries were poisonous when they were red, and the poison somehow came out of them when they turned black so they were then safe to eat.
A childhood belief about general

others believed things like this
- When people talked about serial killers, I thought that they put poison in your cerealAnon
- that the green bit of cucumbers was poisonousAnon
- I used to believe that the dust on top of doors was poisonous.— draconid
- I thought black people were black because they drank chocolate milk. — Shelby
- Dark brown Smarties were poisonous.Anon
- I used to think if a tornado sucked up a poisonous mushroom, it would die.— Will