Preheat your oven according to the chocolate cake mix instructions, typically to 350°F (175°C). Grease a 9x13 inch baking pan. Pour the cake batter into the pan and bake for 25 to 30 minutes or until a toothpick comes out clean. Let the cake cool for 10 minutes.

Once the cake has cooled, poke holes one inch apart all over the surface using the handle of a wooden spoon.

Warm the hot fudge in a microwave-safe container for about 30 seconds until pourable. Carefully pour it over the poked cake, ensuring it seeps into the holes.

In a bowl, mix the chocolate pudding with 1.75 cups of cold milk, whisk until thick, and pour it over the warm cake, spreading it evenly.

Cover the cake with plastic wrap and refrigerate for around 20 minutes to let the layers meld and firm up.

While chilling, mix the remaining pudding with 1.75 cups of cold milk, whisk until thickened, then fold in the thawed Cool Whip and about ¾ of the crushed Oreos.

Spread the topping mixture evenly over the chilled cake and sprinkle the remaining crushed Oreos on top. Serve immediately or chill further before enjoying.