I used to believe that all of the food a person ate went into their legs. As their legs filled up, they had to get them cut off and replaced with newer, longer legs: that's how people get taller!
If people got lazy and didn't change them, then the legs just got fat.
Some people couldn't afford 2 whole new legs, so they would get one new one and take off the other, full leg (amputees).
A childhood belief about general

others believed things like this
- when i was little i always asked my mom if my aunt had ant legs or people legs.— kelly
- I used to think a female daddy-long-legs was called a "mummy-long-legs".Anon
- I used to believe that if I wet my legs in the sea I would become a mermaid.
— andrea - that pickles were octopus legsAnon
- i used to believe that when you did the splits your legs would fall off.Anon
- I used to believe that snakes don't have legs cause ants bit them of.— Lulzy