Mix cake mix with cherry pie filling and eggs instead of box directions. Bake in a jelly roll pan for 30-35 minutes or until cake tests done.
Meanwhile, mix the 3 chocolate mousse packages according to box instructions. Set aside in refrigerator. When cake has cooled, cut it into small squares.
In a large punch bowl, layer 1/2 cake cubes, 1/2 chocolate mousse, 1/2 Cool Whip, 3 crushed candy bars. Repeat layers. Chill and serve.