Preheat your oven according to the white cake mix instructions, usually to 350°F (175°C). Prepare the cake batter as directed, dividing it into two bowls. Tint one bowl green and the other purple, then bake for 25-30 minutes.

While the cakes cool, whisk the instant vanilla pudding mix with 2 cups of cold milk in a mixing bowl for about 2 minutes until thickened. Let it sit undisturbed for 5 minutes.

Crush the chocolate sandwich cookies in a resealable bag using a rolling pin or pulse them in a food processor to create fine crumbs.

Once cooled, remove the cakes from the pans and slice them into ½–1-inch cubes for easy layering.

Layer green cake cubes, vanilla pudding, crushed cookies, and whipped topping in clear cups, repeating until full.

Decorate with sprinkles and add optional toppings like edible eyeballs before chilling the trifles in the refrigerator for at least 30 minutes.