Pour the fruit punch and cherry juice into a large pitcher or bowl, stirring gently to combine and mix the vibrant red hues.
Add the simple syrup or grenadine, stirring until the mixture turns a deep, blood-red color and the syrup is fully integrated.
Gently pour in the lemon-lime soda, allowing the liquid to bubble up and create a lightly fizzy appearance, mixing slowly to preserve the carbonation.
Fill the punch with plenty of ice cubes, which chills the mixture and adds a shimmering, icy look to the drink.
Stir everything gently one more time to ensure all ingredients are evenly distributed and the punch is thoroughly chilled.
Serve the Vampire Punch in glasses, garnished with orange slices or spooky candies if desired, and enjoy the vibrant, blood-red beverage.