I was attacked by what could best be called a warren of rock rats today. Five of them squeezed out of all-but invisible cracks in the rock to attack my ankles, and five of them ended up on the end of my blade.
(Where they promptly disintegrated, which, gotta admit, still creeps me out.)
Anyway, when they were all gone I realized that the area they’d squeezed out of had also disintegrated, and there was a really big sinkhole where it had been.
At the bottom of that sinkhole, I found iron ore.
So that was either good planning or good luck.