Prepare the chocolate cake mix according to the package instructions, typically combining with eggs, oil, and water. Pour the batter into a greased 9x13 inch baking dish and bake in a preheated oven at 350°F (175°C) for 25–30 minutes. The cake is done when a toothpick inserted in the center comes out clean. Let the cake cool on a wire rack for about 10 minutes.

Once the cake has cooled, use the handle of a wooden spoon to poke holes evenly across the surface, ensuring they are spaced out.

Warm the hot fudge in the microwave for about 30 seconds, or until pourable. Carefully pour the warm fudge over the cake, ensuring it seeps into all the holes. Cool completely for about 20 minutes to firm up the fudge.

In a mixing bowl, combine one package of instant chocolate pudding mix with 1 cup of cold milk. Whisk until thickened, about 2 minutes. Pour this layer over the cooled cake and spread evenly. Refrigerate for about 20 minutes to set.

Mix the second package of chocolate pudding with 3/4 cup of cold milk until thickened, about 2 minutes. After the first layer has set, gently spread this second pudding layer on top.

Fold the thawed Cool Whip into the second pudding layer until combined. Mix in 3/4 of the crushed Oreos and spread over the cake.

Top with the remaining crushed Oreos, sprinkling them across the surface for crunch. Serve immediately or refrigerate until ready to enjoy.