Mix the vanilla frosting with neon green food coloring until evenly tinted. Spoon a generous mound onto each cupcake, then immediately sprinkle purple sprinkles over the top before the frosting sets.
Pipe a tiny dot of brown decorating frosting onto each large marshmallow. Press one M&M Mini into the dot to look like a pupil. Repeat for all large marshmallows and let them dry completely.
Stick a toothpick into the bottom of each marshmallow eye, then push the other end of the toothpick into the cupcakes however you like (some looking up, some sideways).
Notes
Nutrition Information (per serving): Calories: 787, Total Carbs: 126g, Net Carbs: 125g, Fats: 29g, Protein: 5g.