Chill all ingredients: Keep the sherbet, juice, and soda refrigerated or frozen until right before the party so the punch stays cold without melting ice too quickly.
Add sherbet to bowl: Scoop large portions of orange sherbet into a large punch bowl. Let it sit for about a minute until the edges turn soft and glossy.
Pour in pineapple juice: Slowly pour the chilled pineapple juice over the sherbet. Stir gently just enough to break the sherbet into soft chunks, not a smooth liquid.
Add food coloring: If using, stir in a few drops of green or orange food coloring until the punch reaches a spooky, vibrant shade.
Pour soda last: Right before serving, pour the lemon-lime soda slowly down the side of the bowl to keep the fizz. Stir only once, very gently.
Add ice and garnish: Drop in the ice ring or ice cubes to keep the punch cold. Float gummy worms or candy eyeballs on top for a playful Halloween look.
Serve immediately: Ladle the punch into cups while the sherbet is still swirling through the liquid, within about 5 minutes of adding the soda for the best texture and fizz.