The Watermelone Hat is a obtainable hat in the PFS store. It's a watermelon on your head.
When your mother said one-of-your-five-a-day, I'm pretty sure she didn't mean carve out a watermelon and wear the other skin on your head.
While it is rather tasty, the squishy and wet parts put me off from this. I'm pretty sure that even the skin is too heavy for your head.
Still, a great way to teach kids to eat fruit.