Yield: 18 servings - 5 points per serving for blue, green and purple
Preheat oven to 325 degrees F.
Add the cake mix, cocoa powder and Diet Coke to a mixing bowl. Use a hand mixer on medium for 2 minutes.
Spray a 9x13 baking pan with cooking spray. Add the cake batter and bake for 34-38 minutes.
Let the cake cool completely.
Add the cream cheese, powdered sugar and vanilla extract to a mixing bowl. Use a hand mixer to combine.
Spread evenly over the cake.