Halloween Rainbow Cake

Directions

1. 1
   Preheat oven to 325°F. Generously grease and flour a 12-cup bundt pan.
2. 2
   Make each cake batter separately, as directed on boxes. Divide the white cake batter into two separate bowls. Add orange food coloring to one bowl and mix to the desired color. Add purple to the other bowl and mix to the desired color. Pour 2/3 of the chocolate cake batter into a bowl and mix with a few drops of the black food coloring. Use the remainder of the batter for cupcakes or another use. (You won't need the rest of the batter for this cake - however, we got about 12 mini cupcakes with our leftover batter).
3. 3
   Pour 1/2 of the black chocolate cake mix into the bottom of the greased pan. Carefully pour the purple batter over the chocolate. Do not stir it. Pour the orange batter over the purple batter and pour in the remainder of the black chocolate batter. Bake as directed on box or until toothpick inserted in center comes out clean. (There should be a cooking time for a bundt pan on the box.) Cool 5 minutes. Turn pan upside down onto cooling rack. Allow cake to cool completely; about 30 minutes.
4. 4
   Once cake is cool, equally divide your frosting into 2 bowls. Use the food coloring to make one bowl orange and one bowl purple. Put each frosting into a piping bag and drizzle the frosting on the cake. We did the orange frosting first and then went over it with the purple.