When I was little my parents used to make me toast, use cookie cutters to cut it into interesting shapes, and then put butter, jelly, or peanut butter on the shapes...it was easy to make and I was a really finicky kid.
Anyway, one day my mom accidentally put peanut butter *and* butter on a piece of toast - I didn't expect it and I guess I had a weird reaction. My dad asked what was wrong and I told him about the peanut butter-butter combination, and he exclaimed "poison!" Now I realize he just meant that it didn't sound like a particularly appetizing mix, but then I thought he meant it was *actually* poison. I started crying *really* loudly because I thought I was going to die.
A childhood belief about dangerous food

others believed things like this
- I thought that barf was what they used to make peanut butter and jelly sandwiches!— Maan o' War
- I used to believe that my mother invented peanut butter and jelly sandwiches. Anon
- My mother told me if I ate too much butter I'd get worms. I didn't eat too much butter...— Dicky
- My daughter thought that ear wax was peanut butter.— Bobbiemac
- When I was a little boy, I thought that hair was made out of peanut butter.Anon
- I used to believe that peanut butter was lobster poo.— PaulH(nz)