Crush the cookies: Pulse the chocolate sandwich cookies in a food processor until they form fine, sandy crumbs, about 30 seconds. Set aside about 1/2 cup of crumbs for topping the finished cups.

Whisk the pudding: In a large bowl, whisk the pudding mix with the cold milk for about 2 minutes, until it thickens enough to coat the back of a spoon. Let it sit in the fridge for 5 minutes to set slightly.

Fold in whipped topping: Gently fold the whipped topping into the pudding until no white streaks remain and the mixture looks light and fluffy. Avoid overmixing so it stays airy.

Layer the crumbs and pudding: Spoon a layer of cookie crumbs into the bottom of each clear plastic cup, then add a layer of the pudding mixture. Repeat the layers once more, ending with pudding, until the cups are nearly full.

Top with reserved crumbs: Sprinkle the reserved cookie crumbs evenly over the top of each cup, patting them down lightly so they resemble loose soil.

Decorate each cup: Press a candy pumpkin and a gummy worm into the crumb layer of each cup, and tuck in a piece of green licorice as a vine if using.

Chill before serving: Refrigerate the cups for at least 1 hour so the pudding layers set firm enough to hold their shape when scooped with a spoon.

Serve: Pull the cups straight from the fridge and serve cold, with a spoon tucked into each one for digging through the layers.