Add 2 cup milk to mixing bowl and sprinkle 1 (3.9 ounce) box instant chocolate pudding mix over it. Then, whisk for 2 minutes or until thoroughly combined. Set aside to thicken.
Place 15 Oreo Chocolate Sandwich Cookie inside zip-top plastic bag and close bag securely. Roll over the bag with a rolling pin until the cookies are crushed to resemble "dirt." (Or, use a food processor for more finely ground "dirt.")
Gently fold 1 tub (8 ounce) tub Cool Whip into pudding until combined.
Assemble dirt cups by layering ingredients in clear cups as follows: cookie crumbs, pudding, 24 gummy worm, and cookie crumbs. (Make sure some gummy worms are peaking out from the "dirt!")