This type of card is called a "Center Step" card. For the main image I used a technique called "Ghosting". I stamped a bat in versamark ink all over my paper and let dry. Then I sponged on top of the images with Distress inks (Pumice Stone and Black Soot). The versamark resisted the ink and you can see it coming through. Then I stamped the bat a few more times with Pumice Stone and Mikes Spooky Tree in Black Soot. I put glitter on the bats and used an old Stampin Up! pumpkin for a bit of colour.
Here's a close up of the ghostly bats: