When you pop watermelon into the freezer, things get a little frosty. Here's the scoop on what happens: As the watermelon freezes, ice crystals start forming inside the fruit. These ice crystals break down the cell walls and insides of the fruit, causing them to change texture. After freezing, you're not going to want to try and serve them fresh! But don't worry, even if frozen watermelon isn't exactly the same as fresh-off-the-vine stuff, it can still be a star player in smoothies, slushies, and, of course, these delectable Frozen Watermelon Margaritas!