Mix the chocolate pudding mix with cold milk in a bowl until the mixture thickens and is smooth, about 3-5 minutes. Set aside in the refrigerator to chill and firm up.
In a separate bowl, prepare the vanilla pudding following the package instructions, then chill it until ready to assemble.
Layer a generous spoonful of crushed cookies into the bottom of each serving cup to create the 'dirt' base, pressing lightly to form a layer.
Spoon the vanilla pudding over the cookie crumbs, filling each cup about halfway and smoothing the top with a spatula or spoon.
Add another layer of crushed cookies on top of the vanilla pudding to mimic dirt on the second level and press gently.
Spoon the chocolate pudding over the second layer of crumbs, creating a dark, rich top layer that resembles moist soil or dirt.
Decorate each cup by inserting cookie tombstones into the pudding, pressing gently so they stay upright, and embed gummy worms so they appear to be slithering out of the earth.
Use a tiny dab of frosting or melted chocolate to secure the cookies if needed, and place additional gummy worms for extra spookiness.
Refrigerate the cups for at least 1 hour to let the pudding set completely and flavors meld.
Once chilled, serve the Graveyard Pudding Cups directly from the refrigerator, delighting viewers with their spooky, layered look and playful decorations.