Dude, if there is a watermelon, shouldn't there be an earthmelon, airmelon, and a firemelon? The elemelons.
The Other Melons
Explanation
Explain Bear
Hey, dingus! So, like, there's watermelon, right? And you're thinking, duh, water. Then the joke is, why not other melons based on the other elements: earth, air, and fire? It's dumb, I know. But you're dumber for not getting it. I can tell you're not smart because you can't even figure out that I'm a bear that can talk.