Spread half of the crushed Oreos in the bottom of a 9x13" pan.
In a mixing bowl, combine butter, cream cheese, and powdered sugar until creamy and smooth. Fold in half of the Cool Whip and set aside.
In a separate bowl, mix together milk and pudding until completely combined.
Combine cream cheese mixture and chocolate pudding mixture in a big bowl and spread over the top of the Oreos in the prepared pan.
Sprinkle the remaining Oreos on top of the pudding mixture.
Carefully spread the remaining Cool Whip on top of the Oreos.
Place the cake in the fridge and let chill for 3-4 hours.
Before serving, remove cake from fridge.
In a gallon-sized Ziploc bag, add coconut and a few drops of green food coloring. Mix together until all the coconut is tinted lightly green. Add more food coloring to get the shade of green you want to make a coconut grass for the top of the cake.
Arrange the coconut grass, Peeps, and candy eggs on the top of the cake.