MIX cookie crumbs and melted butter; press onto bottom of 9-inch springform pan.
BEAT cream cheese and sugar in large bowl with mixer until blended. Add pumpkin and spice; mix well. Add eggs, 1 at a time, mixing on low speed after each just until blended. Pour over crust.
BAKE 50 to 55 min. or until center is almost set; cool slightly. Carefully spread sour cream over top of cheesecake. Run knife around rim of pan to loosen cake; cool before removing rim.
MICROWAVE chocolate and 1 tsp. butter in microwaveable bowl on MEDIUM (50%) 30 sec.; stir until chocolate is completely melted. Drizzle over cheesecake in spiral pattern. Starting at center of cheesecake, pull toothpick through lines from center of cheesecake to outside edge to resemble a spider’s web. Refrigerate 4 hours.