Preheat oven to 325 degrees.
Line 12 muffin tins with paper liners. Place 1 oreo in the bottom of each muffin tin. Set aside.
In large bowl, whip cream cheese and sugar together until smooth.
Stir in vanilla, pumpkin, egg, cinnamon, nutmeg, flour and salt until combined.
Scrape sides of bowl and whip mixture until completely smooth.
Spoon mixture evenly over oreos. Bake 20-25 minutes or until cheesecakes have set. Remove from oven to cool.
Transfer warm cheesecakes out of tin and finish cooling on cooling racks. Gently remove paper wrappers.
Microwave chocolate chips with vegetable oil until smooth and completely melted. Spoon chocolate into a piping bag with a small round tip.
Pipe melted chocolate in a spiral on top of cheesecakes.
Drag the end of a toothpick or wooden skewer through the chocolate to create a spiders web look.
Repeat with remaining cheesecakes. Refrigerate until ready to serve.