Remove the rind from the watermelon and cut the flesh into cubes. Place into a gallon-size freezer bag and place flat in the freezer so the fruit is in a single layer. Freeze for at least 4 hours until solid.
Add the frozen watermelon, wine, vodka, and lime juice to a blender. Cover and blend until slushie.
Pour into glasses and garnish with a piece of watermelon and a lime slice. Serve immediately.
Notes
If you want the slushie thicker, you can add a few ice cubes and blend until your desired consistency is reached.
Using a flavored vodka adds a special twist to the slushie. (Raspberry is delicious!)
This recipe can easily be doubled as long as your blender is large enough.