Prepare cake batter and bake in 13x9-inch baking pan as directed on package. Cool completely.
Transfer cake to cutting board; cut into pieces using diagram 1. Arrange cake pieces on cake board or large platter to form the witch's head, nose, hair and hat as shown in diagram 2.
Frost and decorate with Evil Embellishments as listed below. Store in refrigerator.
For frosting, add milk to dry pudding mix in medium bowl. Beat with whisk 2 minutes or until well blended. Gently stir in whipped topping. Remove 1 cup of the pudding mixture to use for the hair; spread remaining pudding mixture onto cake.
Evil Embellishments-Scary Face
For scary face and witch's wart, use the chocolate chips.
Evil Embellishments-Ghoulish Green Hair and Witch's Hat
For ghoulish green hair, stir green food coloring into the reserved 1 cup pudding mixture. Spread onto the head as desired. For witch's hat, sprinkle top and sides with cookie crumbs.