Wall Skeleton

You cannot craft this. It comes off the Dungeon walls where it was already hanging, and only in the stretches backed by slab walls, so a good half of the rooms you pass through will have none. Take them as you go. Coming back later for decoration means clearing the Dungeon population a second time over a piece of wall art.

It hangs like a painting, on the wall rather than on the floor, so it costs you no room space. Two or three spaced along a corridor do more for a crypt or a laboratory build than a single one hung over a doorway.