Prepare cake batter as directed on the box. Divide batter in to 3 separate bowls.
Dye one yellow, one orange. (Leave the final one white).
Spray a 13x9 pan with non stick spray. Evenly spread the yellow layer in the bottom of the pan. Freeze for 20-30 minutes.
Pour orange batter over the yellow batter. Gently spread until it is somewhat even. Freeze for 20-30 more minutes.
Preheat oven. Gently spread white cake batter over top of the yellow batter. Allow cake to come to room temperature for at least 30 minutes.
Bake according to the box directions. Immediately after it's done baking poke holes in the cake with the handle of a wooden spoon. Pour sweetened condensed milk over the cake. Refrigerate overnight.
Spread with thawed whipped topping and garnish with a generous amount of candy corn.