1. Cut pound cake in half lengthwise. Then slice across every 2 inches to create 10 rectangles.
2. Mix green and yellow food coloring in vanilla frosting (one yellow drop for every two green ones). Place 2 tablespoons of frosting into a small zip-top bag; set aside. Spoon remaining frosting into a microwaveable container and heat on high, stirring every 15 seconds, for about 45 seconds or until it is the consistency of heavy cream. Pour frosting over cake pieces to coat completely. Refrigerate for 30 minutes, or until set.
3. To decorate: Spoon dark-chocolate frosting into a 1-quart freezer zip-top bag. Snip a very small corner from both the green and chocolate frosting bags. Place each cake on top of a graham cracker. Pipe a nose on the center of each cake and use green frosting and attach a green M&M to each side of the cake for “bolts”. Press two jumbo confetti sprinkles in each cake for eyes; then use dark-chocolate frosting to secure two black confetti sprinkles on top to form pupils. Pipe on hair, eyebrows, and scar with chocolate frosting. Squeeze a wiggly line of red icing for mouth.