Has it been run over? The area around it does look kind of roughed up, so that seems plausible to me, but if you look along the margins of the "Blob" rock you'll see it appears that the formation has been tilted in such a way that the rock being "consumed" is now lying flat on the ground where it was once standing up at a fairly sharp angle. If that's a correct interpretation, then the plopping of the "Blob" fluid, whatever it was, must have been fairly gentle on the one hand, and it must have been able to slide down the rock it landed on.

Ejecta melt? Sure, why not? But where would it come from? Not that I expect an answer; there are many potential sites, and given dynamics of impact and ejection on Mars, it could have been very distant.

Would it necessarily be melted rock, or could it be an icy material? I tend to favor an icy material over laval (is that a word? ;-)) because of the shape (so drop-shaped) of the formation, and because of its deposition upon a rock -- a nice angular rock such as we see all over the planet -- and into the pre-existing soil or regolith. You can see where the formation has been moved that the soil/regolith continues uninterrupted underneath. It would be very surprising -- though probably not impossible -- for lava to be deposited just here and in just that manner, on top of soil, and a rock that happened to be in the way.

Mud? All right, why not? But if mud, would it have to be from impact ejecta or could it be from a particularly energetic eruption from the interior? And if there was such an eruption, where would it originate?

We tend to think of eruptions entirely in terms of lava and such, at great rock-melting temperatures. But is that the only way? On Mars, would it be possible for "room temperature" material to act like multi-thousand degree lava?

I recall the salt deposits that appear to be extruded from the interior... how likely is fluid (whether water or something else) to be associated with those deposits? Could eruptions of "room temperature" fluid have occurred as part of the salt extrusion?

Just wondering...

Cheers,