Spiderweb Pumpkin Cheesecake

Combine wafer crumbs and butter; press onto the bottom and 1 in. up the sides of a greased 10-in. springform pan. Set aside. In a mixing bowl, beat cream cheese and sugars until smooth. Add eggs; beat on low speed just until combined. Whisk in pumpkin, cornstarch, vanilla and pumpkin pie spice just until blended. Pour into crust. Place on a baking sheet. Bake at 350 degrees F for 60-65 minutes or until center is almost set. Cool on a wire rack for 10 minutes.
Combine topping ingredients; spread over filling. Bake at 350 degrees F for 6 minutes. Cool on a wire rack for 10 minute. Carefully run a knife around the edge of pan to loosen; cool 1 hour longer. Refrigerate overnight. Remove sides of pan; set aside.
For spiderwebs, draw six 3-in. x 2-in. half circles on two sheets of parchment paper on top; tape both securely to work surface. In a saucepan, bring the sugar, cream of tartar and water to a boil over medium heat. Boil, without stirring, until mixture turns a light amber color and candy thermometer reads 350 degrees F. Immediately remove from the heat and stir. Cool, stirring occasionally, for 10-15 minutes or until hot sugar mixture falls off a metal spoon in a fine thread.
Using a spoon or meat fork, carefully drizzle syrup over half-circle outlines and inside the outlines to form spiderwebs; reheat syrup if needed. Cool completely. Place melted chocolate in a resealable plastic bag; cut a small hole in a corner of bag. Pipe 1-in. spiders onto parchment or foil; cool completely. With remaining melted chocolate, pipe two or three dots on each web; attach spiders.
Remove sides of springform pan. Cut cheesecake; place a web on top of each slice and remaining spiders on the side. Refrigerate leftovers.