First, spray a 9x13 pan well with baking spray. Prepare cake mix according to package directions, pour into prepared pan, and bake as directed.

Let cake cool to room temperature, then use the handle of a wooden spoon and poke holes all over the surface of the cake (be sure to poke all the way through!).

In a large bowl, prepare the pudding according to package directions. When it's still pretty thin and liquid, pour all over the surface of the cake. Use a spatula to smooth the surface.

Refrigerate for at least 1hr.

Lightly crush Oreo cookies, and sprinkle all over the cake surface. Serve immediately and store leftovers in the fridge.