A recent (?) archaeological mystery: The Scary Iron Head:
The thing I had stepped on was shaped like a tiny mountain of metal. I started uncovering it with my hands. As I dug, I found what looked like a mouth, an eye socket, and another. For some reason I will never know, there was a large, iron head buried in the yard! I never would have seen it had I not actually stepped right on it.

I’m guessing bad art. I’d certainly bury it out in the yard if I ever got something like it.
Matter of fact, I did get something like it, albeit not scary. A few years ago someone gave me a sculpture in what seems like iron. It’s like a weird fossil fish against a background. Weighs a ton as well.
I suppose I ought to bury it in the back yard and see what happens in 50 years.
Not like I figure I’ll even be here in 50 years to find out.
(HT Amaxen at TPW)