Murder By Chocolate
In a large bowl, crumble cake. Layer a 9x13x2 inch bowl with 1/3 of the cake, cover with 1/3 of the mousse, crumble the Heath bars and sprinkle 1/3 over bowl. Top with some of the Cool Whip. Repeat layers until all ingredients are used up. Make sure the top is Cool Whip. Shave some bittersweet chocolate over all and serve.