Let the creepiness begin at the curb with these super spooky Halloween decorations. Pages 9 of 11 See All Terrifying Tombstones You can make these out of plain or smooth styrofoam (available at craft or hardware stores) or repurpose polyurethane or high-density gray foam, both of which are slightly flexible and used as packing material. Click here for instructions. Pages 9 of 11 See All