Mix up a chocolate cake mix according to the directions but bake it in a cookie sheet (the one with the little sides) for 15-20 minutes at 3:50 until done (toothpick test).
Let cake cool completely. Before serving, pierce cake with fork all over.
Pour a can of sweetened condensed milk over cake.
Top with a container of Cool Whip or whip cream.
[ Some people put crushed Heath Bars or butter brickle between the milk layer and the cool whip but I find that to be overkill. 'Sup to you...]
You can dress it up with sprinkles, nuts, shaved chocolate or whatever or serve it plain. It has been my experience that it doesn't last long enough to be admired.
Serve immediately after putting Cool Whip on.
Oh. My. God.