Use a food processor or zip-top bag + rolling pin to crush cookies into fine crumbs (reserve 2–3 tbsp for topping).
Whisk chocolate pudding mix with cold milk in a bowl until thickened (about 2 minutes). Set aside.
In a separate bowl, beat cream cheese, butter, and powdered sugar until smooth. Fold in Cool Whip.
In a 9x13-inch dish (or individual pots), layer:Half the Oreo crumbs (like "dirt").All of the cream cheese mixture.All of the chocolate pudding.Remaining Oreo crumbs. Press gummy worms into the top layer. Chill for at least 2 hours before serving.