Crush Oreo cookies into fine crumbs and divide in half - one half for layers, one half for the topping.
Beat softened cream cheese and butter until smooth. Add powdered sugar and mix until no lumps remain.
Whisk chocolate pudding mix with whole milk for 2 minutes, then let sit for 5 minutes to thicken.
Fold the pudding into the cream cheese mixture, then gently fold in the whipped topping in two additions.
Layer half the Oreo crumbs in the bottom of the dish, then spread the filling evenly on top.
Cover the filling completely with the remaining Oreo crumbs. Add gummy worms on top if using.
Refrigerate covered for at least 4 hours or overnight before serving cold.
