Bake 9 x 13 inch chocolate cake and let cool. Cut into 1 inch squares. Place 1/2 cake in bottom of punch bowl. Mix 2 small packages of chocolate pudding (instant) and 3 cups milk. Spread 1/2 of pudding on top of cake, 1/2 large Cool Whip over pudding. In food processor chop 6 Heath bars; sprinkle 1/2 of the chopped Heath bars over Cool Whip. Repeat layers once again.