PLACE drink mix in large bowl. Add hot water; stir until drink mix is completely dissolved. Add cream cheese; beat with electric mixer on medium speed until well blended. Gently stir in whipped topping with wire whisk. Remove 1/2 tsp. of the cream cheese mixture for later use; set remaining cream cheese mixture aside.

CRUSH 3 of the cookies; place crumbs in shallow dish. Set aside. Cut cake lengthwise in half. Frost cake top with some of the remaining cream cheese mixture. Dip in cookie crumbs until evenly coated; set aside. Place cake bottom, cut-side up, on serving platter; frost top and sides with some of the remaining cream cheese mixture. Place cake top next to cake bottom to resemble coffin lid. Frost sides and cut-side of cake top with the remaining cream cheese mixture.

PLACE remaining cookie on centre of cake bottom to resemble a body. Line up two rows of 3 mini marshmallows each at bottom of body for the legs. Place 1 mini marshmallow on each side of body for the arms. Add large marshmallow to top of body for the head. Using reserved 1/2 tsp. cream cheese mixture, attach 1 mini marshmallow to each side of head for the ears. Use decorating gel to draw mouth and eyes. Top cake with fruit snacks. Store in refrigerator.