Preheat oven to 350 degrees. Spray or line a standard muffin tin.
Add cake mix and pudding to a large mixing bowl. Using a hand or stand mixer, mix in your water, oil, and eggs on medium until well incorporated.
Separate the batter evenly between the 4-mixing bowls. Add the pink food coloring to one, the blue to the another, the purple to the 3rd and the black to the 4th.
Alternate adding the colored batter into the muffin tin until each is about 2/3 full. Bake for 18-20 minutes, or until a toothpick comes out clean. Allow to cool completely before adding the frosting.