Mix 2 cups of the cookie crumbs, 1/4 cup of the sugar and the melted butter with fork in 13x9 in. baking pan until crumbs are well moistened. Press firmly onto bottom of pan to form crust. Refrigerate. Beat cream cheese and remaining 1/4 cup sugar in med. bowl with wire whisk until smooth. Gently stir in 1/2 of the whipped topping. Spread evenly over crust. Stir boiling water into gelatin in med. bowl 2 min. or until completely dissolved. Mix cold water and ice cubes to make 1 1/2 cups. Add to gelatin; stir until slightly thickened (consistency of unbeaten egg whites). Remove any remaining ice. Spoon gelatin over cream cheese layer. Refrigerate 3 hr. or until firm. Spread remaining whipped topping over gelatin just before serving; sprinkle with remaining 1/4 cup cookie crumbs. Decorate sandwich cookies with icings to make "tombstones." Stand tombstones on top of dessert with candies to resemble a graveyard. Cut into squares to serve.