Death by Chocolate

1 box chocolate cake mix
1 cup Kahlua liqueur
3 (5 ounce) boxes Jell-O chocolate mousse
3 (8 ounce) containers Cool Whip
6 Heath bars, crushed

Bake the cake as directed in a 13 x 9-inch pan. Let the cake cool, then poke it with a fork all over. Pour Kahlua over the cake and refrigerate overnight or several hours. Make the mousse as per package directions and layer it with the Cool Whip and crushed Heath bars.