Fill your cocktail shaker with ice.
Add tequila, vodka, triple sec, lime juice, cranberry juice, simple syrup, and pomegranate juice.
Shake well for about 15 seconds until chilled.
Strain into a margarita glass filled with fresh ice.
In a small bowl, mix raspberry syrup or grenadine with red food coloring (and black if using).
Fill a syringe with the syrup mixture.
Place the syringe in the drink and let it ooze into the cocktail for dramatic effect.
Add a splash of club soda or lemonade if desired.
Garnish with a lime wedge or apple slice.
Rim the glass with salt or black sugar before pouring (optional).