Preheat oven to 350 degree F. Grease the 9x13 inch pan.
Melt the butter in microwave.
Mix in the softened cream cheese, vanilla extract and powdered sugar.
Stir in the semi sweet chocolate chips. Set aside.
Take a medium bowl. Combine cake mix, pumpkin puree and pumpkin pie spice.
Pour this cake mix batter into greased pan.
Take your cream cheese mix and drop spoonfuls on the batter. Make sure to keep some gap between each dollop.
With your spoon, swirl the cream cheese mix into the batter.
Bake for 45 minutes or till the inserted toothpick comes out clean.
Allow it to cool for sometime. Serve warm slices.