Preheat your oven to 350°F (175°C) and prepare the chocolate cake mix according to package instructions. Pour the batter into a greased 9x13 pan and bake for about 30 minutes until a toothpick comes out clean. Allow to cool for 10 minutes.

Poke holes about 1 inch apart across the surface of the cake using the handle of a wooden spoon.

Warm the hot fudge in the microwave until pourable, about 30 seconds to 1 minute, then pour evenly over the cake allowing it to seep into the holes.

Let the cake cool completely at room temperature for 30 minutes to 1 hour.

In a medium bowl, whisk together the chocolate pudding mix and 3 cups of cold milk for about 2 minutes until thickened. Spread the pudding evenly over the cooled cake.

Cover the cake lightly with plastic wrap and refrigerate for an additional 20 minutes.

Mix the remaining chocolate pudding with milk, fold in the Cool Whip until combined, and mix in three-quarters of the crushed Oreos. Spread over the cake and top with remaining crushed Oreos.

Serve immediately or refrigerate until ready to serve. Best enjoyed fresh.