Place ice cubes or frozen grapes in your shaker or mixing glass.
Pour in grape juice, lemon-lime soda, orange juice, apple juice, lime juice, and pineapple juice.
Add the simple syrup (or honey) and grenadine.
Lightly muddle blueberries, blackberries, or grape slices in the shaker for a flavor boost.
Shake or stir the mixture well to combine all ingredients.
Strain the mixture into a tall glass (or pour directly from pitcher if making a larger batch).
Add fresh berries and grape slices as garnish.
Top with mint leaves if desired.
For a spooky fog effect, carefully drop in a small piece of food-safe dry ice just before serving. Wait until the fog clears before drinking.
Taste and adjust sweetness if needed by adding more syrup, honey, or grenadine.
Serve immediately and enjoy the spooky vibes!