Make skull ice cubes a few days ahead. Add ⅓ cup water to each stemless wine glass and freeze for a minimum of 1 hour. Remove glasses and skull ice cubes from the freezer and place the skull cubes face up in the stemless wine glass. Add an additional ¼ cup of cold water around the skull using a squeeze bottle or syringe to make sure the water doesn't melt the top of the skull ice cube. Return glasses to the freezer to completely freeze until ready to use. Make a pitcher of your favorite cocktail and serve in pre-chilled polter-iced glasses. As the larger bottom ice melts and begins to float to the top the tapered sides of the wine glasses will keep the skull ice from flipping over. Please enjoy responsibly.