The object is seen moving across the ground before becoming in flight...
Image credit: Rob1979
The thing it moves towards is not a rock, it is some sort of carcass and this flying thing is feeding on it. It could also be a hive type structure. This would be understandable given an alien robot is driving towards it and it may be looking for a safe haven.
Rob has done a side by side comparison to show the object is not only in both, but moving in the same manner. The cameras are mounted on the opposite side to each other on the rover, this is why the images appear slightly different. The main thing is that the object is seen on 2 camera's, possibly more. It is seen moving towards somewhere it could hide.
The final image of the bug on top of the hollowed out thing (carcass, rock, hive) is very interesting.