Prepare, bake, and cool cake according to package directions. Except make the cake in 10-cup fluted tube pan with ridges (to resemble a pumpkin). Measure 1/4 cup vanilla frosting into small bowl. Tint with green food coloring. Place ice cream cone upside down on waxed paper. Frost with green frosting. Refrigerate. Tint remaining frosting with yellow and red food coloring until frosting is desired shade of orange frosting in small bowl. Frost cake with orange frosting. Add green food coloring to make brown frosting. Make eyes, mouth, and nose with brown frosting as desired on pumpkin. Place green frosted ice cream cone in center hole of cake for stem.