When I was a kid, my grampa told me that if you swallow the black seeds inside a watermelon, they would grow into watermelons inside your stomach.
A childhood belief about seeds

others believed things like this
- when you eat the seeds from a watermelon a watermelon will start to grow inside your stomache.Anon
- I used to beleive that if you ate a black watermelon seed a tree would grow in your stomach— anonymous
- If you eat watermelon seeds a watermelon will grow in your tummy and vines will come out your earsAnon
- I used to believe that if you ate a watermelon seed you would grow a watermelon tree in your stomach!!!— Eskimo
- I used to believe that if you ate the pips in apples a tree would grow inside your stomach.— QueenB
- I used to believe that if you swallowed watermelon seeds, they would dance around in your stomach at night.— jaalyn