Heat oven to 375°F. Place paper baking cup in each of 24 regular-size muffin cups. Make and bake cake mix as directed on box for cupcakes. Cool 10 minutes; remove from pans to cooling racks. Cool completely, about 30 minutes. Divide frosting into five separate small bowls. Stir 1 teaspoon desired color gel food color into each bowl. Spoon each color frosting into separate decorating bag fitted with desired tip. Pipe frosting on cupcakes to look like monster's fur. Decorate each cupcake as desired using candy eyeballs and decorating gel. Tips: Use a small star decorating tip for hair on these scary monsters. If you only have one pan and a recipe calls for more cupcakes than your pan will make, cover and refrigerate the rest of the batter while baking the first batch. Cool pan about 15 minutes, then bake the rest of the batter, adding 1 to 2 minutes to bake time.