1Heat oven to 350°F. Place paper baking cup in each of 24 regular-size muffin cups or spray with cooking spray. Make and bake cake mix as directed on box for cupcakes, using water, oil and eggs. Cool 10 minutes; remove from pans to cooling racks. Cool completely, about 30 minutes.
2Tint 1 container frosting with green food color. Tint second container frosting with purple food color. Place green frosting in decorating bag fitted with star tip #109. Place purple frosting in second decorating bag fitted with #109 tip. Pipe green frosting on half of the cupcakes. Pipe purple frosting on remaining cupcakes.
3Attach gummy candies for eyes. With frosting, attach candy eyes in center for eye pupils. Attach licorice pieces for mouths. With dampened kitchen scissors, cut marshmallows into small pieces for fangs. Attach candy corn above eyes for horns and on sides for ears.