My grandfather told me when I was about 4 that if I ate watermelon seeds, a watermelon vine would grow in my stomach.
I thought that was the coolest thing I had ever heard of (I love watermelon), so I ate some seeds, drank some water, swallowed some dirt and stood in the backyard with my mouth open to make sure some sunlight got down there.
I was very disappointed when it didn't happen.
A childhood belief about seeds

others believed things like this
- If you eat watermelon seeds a watermelon will grow in your tummy and vines will come out your earsAnon
- when you eat the seeds from a watermelon a watermelon will start to grow inside your stomache.Anon
- I used to believe that if you swallowed watermelon seeds, they would dance around in your stomach at night.— jaalyn
- I use to believe (thanks to my Mom) that if I swallowed a watermelon seed a watermelon would grow in my belly.Anon
- I used to believe that if I swallowed watermelon seeds, I would get pregnantAnon
- I used to believe that if you ate a watermelon seed you would grow a watermelon tree in your stomach!!!— Eskimo