Heat oven to 350°F (325°F for dark or nonstick pans). Spray two 9x5-inch loaf pans with cooking spray. Make cake batter as directed on box; pour into pans. Bake 32 to 40 minutes or until toothpick inserted in center comes out clean. Cool 10 minutes; remove from pans to cooling rack. Cool completely, about 1 hour.
Trim about 1/4 inch off top of each cake to level. On long serving platter (at least 18 inches), place cakes bottom sides up to make long rectangle.
In small bowl, mix 1/3 cup of the frosting and the green food color until well blended. Frost one-fourth of cake (top and sides) with green frosting for face. Frost remaining cake with remaining white frosting.
Using ribbon tips on decorating icing cans, draw alternating white and blue lines, beginning at edge of green frosting, to far end of cake.
Place 1 green gumdrop on each side of face for ears and 1 for nose. For eyes, press white gumdrops, small ends down, on face. Use decorating gels for eye pupils, eye lashes, nose and lips. Store loosely covered.