In advance: Make turtle shells. Melt and tint 14 oz. candy dark green. Use mold to make 13 medium domes following mold directions. Chill until firm; unmold. Fill with cereal treat mixture. Seal bottom with melted candy.
Bake and cool cupcakes. Ice tops smooth. Tint fondant: 6 oz. light green (head, legs, tail); 2 oz. medium green (spots); 1 oz. dark green (edge of shell opening); 1/2 oz. black (headless shell); reserve 1/2 oz. white. For spots, roll 1/4 in. balls of medium green. Use fingers to flatten into assorted shapes about 1/16 in. thick; attach eight to 10 to each shell using damp brush. For feet (on all except headless shells), roll 5/8 in. diameter balls; shape and attach, positioning to match intended pose. For tail, shape a 1/2 in. long teardrop; attach. For head, roll a 1 in. ball. Shape into a 3/4 in. ball head with tapered neck 1/2 in. long and curved to match intended pose. Let dry 10 minutes, then attach in position using melted candy.
For headless shells, roll out black 1/16 in. thick. Cut a 1 in. diameter circle; position for opening and trim away bottom. For neck opening of shells, roll dark green 1/4 in. diameter logs. Attach around neck or
opening using damp brush.
Roll out white 1/16 in. thick. Cut eyes using narrow end of tip 6. Draw pupils and smile with FoodWriter. Position turtles on cupcakes. Position in stand.