At least 1–2 hours before the party, place your pineapple juice, ginger ale (or lemon-lime soda), and fresh lime juice in the refrigerator. All liquids must be very cold — you should feel condensation on the bottles when you take them out. Checkpoint: You are ready to move on when all liquids are thoroughly chilled and feel ice-cold to the touch.

About 5 minutes before you are ready to assemble, remove the lime sherbet from the freezer and set it on the counter at room temperature. Do not leave it longer than 5–7 minutes — you want it soft enough to scoop cleanly, not melted. Checkpoint: You are ready to move on when the surface of the sherbet yields slightly to a spoon without crumbling.

Pour the 2 liters of chilled ginger ale or lemon-lime soda into a large punch bowl first, then add the 2 cups of chilled pineapple juice. Stir gently for about 1–2 minutes to combine — avoid vigorous stirring, which will flatten the carbonation.

Squeeze the juice of 2 limes (about 1/4 cup) directly into the punch bowl. If using green food coloring, add 2–3 drops now and stir gently until the color is evenly distributed. The liquid should look pale green and lightly fizzing. Checkpoint: You are ready to move on when the liquid is well combined and a uniform light green color.

Using an ice cream scoop, add the lime sherbet to the punch bowl one scoop at a time, distributing the scoops evenly across the surface of the liquid. Do not dump it all in at once. Once all the sherbet is in, stir very gently once or twice — just enough to start the foaming reaction. Within 1–2 minutes, a thick frothy green foam will build on top and the punch will turn a vibrant creamy green. Checkpoint: You are ready to move on when the punch looks bright green with active bubbling foam on the surface.

Drape gummy worms over the rim of the punch bowl and let a few float on top for a spooky effect. Add any optional garnishes like plastic eyeballs or a frozen hand ice mold now, placing them in the bowl or on the rim — never use dry ice directly in cups that guests will drink from.

Ladle the punch into cups immediately and serve. Throughout the party, replenish the punch bowl by adding fresh sherbet scoops and a splash of chilled soda as needed to maintain the foam and fizz. The punch is best within 30 minutes of assembly.