Desired candy decorations, such as sugar-free lollipops, sugar-free fruit-flavor circle candies, sugar-free hard candy disks, and sugar-free red licorice (optional)
1Preheat oven to 325°F. Coat twenty-four 2- ½-inch nonstick muffin cups with cooking spray; set aside.
2In a large bowl combine cake mix, the water, egg whites, pureed plums and oil. Mix according to cake mix package directions. Divide batter evenly among prepared muffin cups. Bake for 15 to 18 minutes or until a wooden toothpick inserted in centers comes out clean. Cool in muffin cups on wire racks for 5 minutes. Remove cupcakes from muffin cups. Cool completely on wire racks.
3Meanwhile, for frosting, in a medium bowl combine whipped topping and a little green food coloring, stirring gently until coloring is evenly dispersed. Cover and refrigerate until needed.
4Decide whether you want to make one large critter or several smaller critters. Set aside one cupcake for the head of each critter you are making. Arrange the remaining cupcakes in decorative, winding fashion on cutting board(s) or cake platter(s). Shortly before serving, spoon the whipped topping into a pastry bag fitted with a star tip. Pipe small stars to cover the tops of all of the "body" cupcakes. (Work quickly as the heat from your hands can cause the whipped topping to deteriorate.)
5Spread frosting on the cupcake(s) reserved for the head(s). Cut a 2-inch-long piece of drinking straw for each head; use straw piece(s) to attach head(s) to the critter(s). Decorate head and body cupcakes with candy as desired.