Place the chocolate sandwich cookies in a large zip-top plastic bag and use a rolling pin to crush them into small pieces. Don’t worry about removing the cream filling before putting the cookies in the bag. It will clump together then mix together. Crush the cookies until they are in fine crumbs. A few larger pieces are okay.
Pour the dry pudding mix into a large bowl and add the cold milk. Whisk until all of the dry pudding dissolves and it’s smooth and free of lumps. Let the pudding sit for about 5 minutes, until it thickens.
Add the whipped topping and approximately half of the cookie crumbs. Gently stir everything together.
Divide the pudding mixture evenly between 8 cups. Tap the cups on the countertop a few times to level the pudding, then insert 3 gummy worms into the pudding and press them in a bit so they stay put.
Pour the cookie crumbs over the pudding and gummy worms so that the entire top is covered with “dirt.”