Heat oven to 350°F (325°F for dark or nonstick pans). Make, bake and cool cake as directed on box for 24 cupcakes.
Reserve 2 tablespoons frosting. Tint remaining frosting with food color to make green; frost cupcakes.
For eyes, place 2 cookies near top edge of each cupcake, inserting on end so they stand up. Attach 1 cinnamon candy to each cookie with reserved white frosting. Add dots of white frosting for nostrils.
For mouth, pipe on red icing. Slice gumdrops; add slice to each cupcake for tongue. Store loosely covered.