The frog and shark I saw were both ceramic watermelon-type shells. At first sight I could see how a real watermelon would work and prefer the real thing to more clutter in the cupboards for a few times a year use.
Yup! There are a lot of ideas for crafty watermelon lovers. I tend to cut the whole thing up and put it in a bowl. Boring, but effective. Easiest when Gypsy does all the work like she did this weekend when we both had a bowl of watermelon pieces in my/her fridge.