Preheat oven to 350°F. Prepare muffin tin with liners.
Prepare the crust by stirring together chocolate graham cracker crumbs, brown sugar, and melted butter. Press 2 tablespoons of crumb mixture into muffin tin cups.
Prepare the cheesecake filling. In a large bowl, beat cream cheese until light and fluffy. Add sugar, eggs and vanilla and beat until creamy. Mix in sour cream until smooth.
Fill muffin cups ¾ of the way full. Bake in the middle rack of the oven until edges are set but center slightly jiggles, about 15-18 minutes. Remove and set on cooling rack to cool completely.
Prepare the ganache. Add chocolate chips to a small bowl. Heat up heavy cream in a microwave and pour over chocolate chips. Let sit for a couple minutes until chocolate chips have softened and stir until completely melted and combined.
Let ganache cool and thicken slightly. Add to piping bag and cut a small hole in the tip. Pipe a skeleton face onto the cooled cheesecakes.
Refrigerate until ready to enjoy. Store in an airtight container in the refrigerator for up to 5 days or in the freezer for up to 2 months.