Add the fruit punch syrup, pineapple juice, and a handful of crushed ice into the blender. Blend on high until the mixture is smooth and frothy, about 30 seconds. You should see bubbles forming and the color turning vibrant green.
Pour the bubbly mixture into a large serving pitcher, allowing some foam to spill over for a wild, chaotic look. Then, gently stir in the chilled lemon-lime soda to add fizz and lighten the texture.
Tear the fresh mint leaves into smaller pieces and add them to the punch. Stir gently to release their aroma and a hint of minty freshness throughout the drink.
Once mixed, ladle the Monster Mash Punch into individual glasses. Garnish each with a sprig of mint and maybe a spooky straw or glow stick for extra fun.
Serve immediately and enjoy the bubbling, wild chaos of this festive Halloween drink!