1.
Preheat oven 350 degrees.
2.
Prepare a 9 x 13 x 2-inch pan with cooking spray and flour.
3.
To prepare crust, combine 2 cups cookie crumbs, granulated sugar, and margarine in a small mixing bowl until incorporated.
4.
Press crust mixture firmly into prepared pan and bake for 10 minutes and then chill in refridgerator.
5.
To prepare filling, combine cream cheese and 1/2 cup Cool Whip in a mixing bowl.
6.
In another mixing bowl, combine boiling water and gelatin until completely dissolved.
7.
Mix cold water and ice cubes together to make 1 1/2 cups of water.
8.
Stir ice water into gelatin until thickened. Remove any remaining ice pieces.
9.
Spoon gelatin over cream cheese layer and refrigerate for 3 hours or until firm.
10.
Spread remaining Cool Whip over gelatin layer.
11.
Decorate the sandwich cookies to make them look like tombstones with the white decorator icing.
12.
Sprinkle the cake with remaining 1/4 cup cookie crumbs and decorate as a "graveyard" by poking sandwich cookies (standing up on end) into dessert. Scatter candy and pumpkins around the surface.