1 (18.25 ounce) box white cake mix
1 (3 ounce) box watermelon gelatin
1 1/4 cups water
1/4 cup vegetable oil
2 containers vanilla or cream cheese frosting
Red and green gel food coloring
Preheat oven to 350 degrees F. Grease and flour two 9-inch round baking pans.
In a mixing bowl, combine dry cake mix, gelatin, eggs, water and vegetable oil. Beat on low speed just until moistened then on high for until well blended. Pour into prepared baking pans. Bake for 30 to 35 minutes or until a wooden pick comes out clean. Cool for 10 minutes; remove from pans to wire racks to cool completely.
Set aside 2 to 3 tablespoons frosting for decorating. Place one container into a bowl; tint red. Tint second container green. Place one cake layer on a serving plate; spread with 1/2 red frosting to within 1/4 inch of edges. Top with second cake. Frost top with remaining red frosting to within 3/4 inch of edges. Frost sides and top edge with green frosting. Place reserve white frosting in a small plastic baggie, cut 1/4 inch hole in one corner. Pipe around top edge of cake where green and red frosting meets. For seeds, insert chocolate chips upside down into the cake top.