Hellas Planitia is the dominant elliptical feature just below the center of the picture. North is up and sunlight illuminates the area from the upper left. The approximately 500 kilometer-wide circular feature just above the center is the crater Huygens. This feature is a dust devil. Dust devils are spinning, columnar vortices of wind that move across the landscape, pick up dust, and look somewhat like miniature tornadoes.
Dust devils are a common occurrence in dry and desert landscapes on Earth as well as Mars.
When this dust devil was spied in Amazonis Planitia on April 10th, the MOC was looking straight down. Usually when the camera is looking down the dust devil will appear as a circular, fuzzy patch with a straight shadow indicating its columnar shape. A thin, light-toned track has been left by the dust devil as it moved eastward across the landscape. Usually, such tracks are darker than the surroundings, in this case the light tone might indicate that the dust being removed by the passing dust devil is darker than the surface underneath the thin veneer of dust. Dust devils most typically form when the ground heats up during the day, warming the air immediately above the surface.