We had a bizarre mystery closet in our apartment that had no door and was right next to another closet. We hid it behind a sheet and started calling it "the bat cave". But for Halloween, I decided it needed something different... Here is how to build your own (temporary and storable) bat cave.
You will need:
--junk fabric, enough to cover your area
Step 1: Building the Cave Walls
Follow the instructions on your dye package. To get this gray color, I only dyed my fabric in the black dye for ten minutes instead of thirty.
Make sure your fabric is rinsed and dried!
Step 2: Stalactite/stalagmite structures
On my second try I stuffed them with newspaper and empty foam cans, and that worked pretty well but not the greatest. So make sure you have a frame in the cones!
Make them of varying heights and widths, they don't have to be (and shouldn't be) "perfect".
DO NOT use duct tape! The expanding foam needs air to dry as well as a surface to stick to, and since the duct tape is slippery and will also cause it to dry more slowly, the wet foam will simply slide down your structure and build up at the bottom.