Prepare the Cookie Crumbs. Place the chocolate sandwich cookies in a large resealable plastic bag. Using a rolling pin or the back of a spoon, crush the cookies into fine crumbs. Set aside.
Prepare the Pudding Mixture. In a separate bowl, whisk together the instant chocolate pudding mix, and whole milk until smooth and thickened. Fold in half of the whipped topping until fully incorporated.
Assemble the Dirt Cake. In individual cups or a serving bowl, layer the ingredients as follows: Start with a layer of cookie crumbs at the bottom of the dish. Add a layer of the pudding mixture on top of cookie crumbs. End with a layer of cookie crumbs on top.
Chill and Serve. Cover the Dirt Cake with plastic wrap and refrigerate for at least 4 hours or overnight to allow the flavors to meld and the dessert to set. Before serving, garnish with gummy worms for a fun and whimsical touch.