On Sol 506 Curiosity’s MAHLI acquired an image of a rock which had evidently attracted its, ah, curiosity.

But how so? The front Hazcam records this pair of images acquired at 2014-01-07 23:21:21 UTC and 2014-01-07 23:12:31 UTC, showing the deployment of the MAHLI above the imaged rock.

… but reminding ourselves that Curiosity’s brain resides at JPL, the action depicted must have been motivated by images previously acquired and transmitted, and we have to ask ourselves how this came about. In this case I think there’s a fair record.

We can discern that Curiosity arrived at this position on Sol 504, on which date we see a number of Navcam images of the area, including this double image “panorama” of the MAHLI image location

You can actually see the “MAHLI rock” to the left of the cylindrical joint projecting to the front, and the formation of darker rocks to the right of that are recognizable in the Front Hazcam images. These images were acquired around 2014-01-06 00:59, then around 2014-01-06 02:58, the Mastcam acquired the six images of this panoramic view

and there’s the rather nondescript “MAHLI rock” dead center.

This hardly explains what the particular attraction was, but it does give a record of the event if one is willing to “read between the images” … and I looked at a lot more of them!