The Flash delivers a rush of energy strong enough to make you break the time barrier. Don't worry, this cocktail works its magic thanks to a combination of energy drinks and vodka, not chemicals and dark matter. Place your vodka in the freezer ahead of time to chill. Combine all ingredients in a rocks glass with ice. Stir just enough to combine and garnish with a lemon peel, cut into a lightning bolt, if desired. The flavor is unexpectedly charming, and sure to add a burst of mental speed to your night.