Bring 1 cup of water to a boil in a saucepan.
In a mixing bowl, pour the boiling water over the Jell-O powder. Stir until fully dissolved.
Stir in 0.5 cup cold water, 0.5 cup vodka, and 2 tablespoons tonic water. Mix gently to avoid bubbles.
Pour the liquid mixture into clear shot glasses, filling each about 3/4 full.
Drop a gummy worm or other candy into each shot before the mixture sets.
Place filled shot glasses on a baking sheet and transfer to the fridge.
Chill for at least 4 hours or until fully set.
Decorate with black icing, candy eyes, or more gummies before serving.
Serve cold on a tray or platter for best presentation.