Thread Halloween-shaped gummies onto the wooden skewers and set aside for garnish.
Combine the lemon-lime soda, melon liqueur, rum, pineapple juice and lime juice in the punch bowl, and stir to combine. Add the lime sherbet in scoops and stir until the sherbet starts to melt.
Next, using gloves or a dish towel, break the dry ice into large pieces using a small mallet or ice pick. Carefully place some of the dry ice in the bottom of the cauldron, and store the remaining dry ice in a cooler nearby. Pour about a cup of hot water on top of the dry ice to make it smoke. Place the filled punch bowl on top of the dry ice inside the cauldron and serve with gummy garnishes! Replenish the dry ice and hot water as necessary to keep the smoke effect going.