Preheat the oven to a temperature specified on the box. Grease a 9×13 inches baking dish with baking spray and set aside.

Prepare the cake mix according to the directions listed on the box.

Next, divide the mixture into 3 equal portions. One portion should stay white. Add red food coloring in the second portion, and blue coloring in the third. Stir well until the color dissolves completely.

Then using a spoon, make small droops of each mixture in the bottom of the baking dish. Drops will spread in the greased dish so you should do this quickly. I suggest you drop one color at a time leaving a few inches apart between the drops, then make the drops with the second color, then the third, until you cover the bottom of the pan. Then drop another layer on top until using all mixtures. Finally, tap the baking dish on the counter to flatten the surface, do not spread with the spatula to avoid mixing the colors. Using a toothpick, swirl the colors just a little bit (you want the colors swirled not mixing together). Bake as directed on the box.

When the cake is baked and sits at room temperature for about 10 minutes, poke the cake. Use the handle end of a wooden spoon to poke holes all over the top of the cake, then allow it to cool completely.

In a bowl, combine the instant pudding and milk, whisking until the pudding is dissolved. Before the pudding sets completely, pour it over the cooled cake, trying to fill all the holes completely. Spread remaining pudding on top and place in the fridge to set completely.

When the pudding is set and the cake is completely cooled, top the cake with whipped cream. Mix chilled heavy cream and vanilla extract until soft peaks form. Add powdered sugar and mix until stiff peaks form. Spread over the pudding layer.

Garnish with sprinkles before serving.

Store leftovers in the fridge.