Inspired by a hallway in The Goonies, this heavy stone block is apt to fall from any ceiling without warning. It's actually modelled wrong. It needs to have a hook in the top for a support rope, rather than crossed ropes which would be obvious to bypassers, but it gets the idea across.
This feature began life as a desiccant pill for use by pharmacies to keep medicinal pills dry during storage. I sweet talked the local pharmacist into giving me a dozen or so of them a while back, and have had this one rattling around the bottom of the bits box for some time. Nice to finally put it to use.
For those keeping score at home, this is War In A Box's 500th post: