In a food processor, or in a large plastic bag with a rolling pin, add Oreo cookies and pulse or crush to make coarse cookie crumbs. You should have about 3 cups of crumbs.
In a medium bowl, add pudding mix and milk and whisk for at least 2 minutes. The mixture will be thick.
In the bowl of a stand mixer fitted with a paddle attachment, or with an electric hand mixer, beat cream cheese. On low speed, beat in pudding mixture. Fold in the whipped topping by hand.
In the bottom of a 9-inch by 13-inch baking dish, add 1 ½ cups Oreo crumbs. Top with the pudding mixture, then sprinkle with remaining 1 ½ cups Oreo crumbs. Chill until serving time.
Decorate with Milano cookies (halved and stuck upright into the "dirt"), gummy worms, and flowers if desired.
