Prepare the chocolate pudding according to the package instructions, whisking until smooth and no lumps remain. Chill in the refrigerator for about 10 minutes to set slightly.
Spoon the slightly thickened pudding into individual serving cups or small glasses, filling each about three-quarters full. Smooth the tops with the back of a spoon.
Add a generous layer of crushed cookies on top of each pudding layer to resemble dirt. Gently press the crumbs down to help them stick and create a textured surface.
Insert gummy worms into the cookie crumb layer, angling some to look like emerging from the 'dirt' for a spooky effect.
Add another layer of pudding if desired, then top with more crushed cookies to complete the scene. Decorate with additional gummy worms or small edible decorations if you'd like.
Refrigerate the assembled pudding cups for at least 10 more minutes to set everything in place and allow flavors to meld.