I've ranted a bit this last week about how we have to be so careful to not get carried away interpreting the shapes we find in the rover images. So this morning I'm looking through the latest releases, and my tired old brain almost went into gymbal lock when I saw this:

(click for full-size)

It took me a while to pin down what I think it really is. The shadows are tricky, and there's a distinct impression that it's a ring lying partially on top of the ground, partially buried. But this PanCam image puts it in proper context:

Correlating the other shadows, it's actually an impression in the ground. Looks like the RAT was shoved down into the ground, at a slight angle, for some reason. I don't know why they'd want to grind dirt, but that's clearly what it is. Maybe they just wanted to get an indication of soil compaction (oops, I don't think I should say "soil" since that implies organic matter, but you know what I mean).

Kinda fun, huh?