Place the diced pineapple, ice, sherbet lime, and vodka in the blender.
Blend at maximum speed for about five minutes. Turn off the blender and carefully uncover.
Add a drop of the food coloring of your choice. We chose green, but you could use another. Beat for a couple more minutes.
Add the ginger ale and stir with a spoon.
With a sharp knife, cut the lime into thin slices. Make a thin incision on the side of each lime, to place it on the rim of the glass.
Put some gummy worms on the bottom of each glass. Serve the witches brew in small glasses garnished with lime wedges and gummy worms.