In this VIS image, taken by the NASA - Mars Odyssey Orbiter on April, 10th, 2014, and during its 54.664th orbit around the Red Planet, we can see an unusually-looking (as far as its Floor is concerned) and extremely ancient Unnamed Impact Crater located on the Margin between the Martian Regions known as Terra Sabaea and Utopia Planitia. The peculiartity of this Impact Crater is that its Floor (most of it and, in particular, its Outer portion) is filled with some kind of Material and shows a peculiar Grooved Surface.
The Grooves, if you look carefully, are (almost) parallel to the Impact Crater's Inner Rrim, and this circumstance may indicate that the Material that we see now fully solidified on the Crater's Floor, once, most likely eons ago, was (being, probably, very dense, nut still semi-fluid) flowing away from the Rim itself.
However, if this hypothesis were proven (one day) as the correct one, then it would be reasonable to believe (---> assume) that the aformentioned Flow was - probably - supported (---> sustained/facilitated in its course/way down) by the (strong) presence of Volatiles (like Water Ice Particles) that were trapped inside the Fill Material and, in time, slowly melted, or evaporated (or, if you wish, sublimated), thus making the Fill Material itself loose enough to slide down inside the Crater and then forming that unusually-looking "Wave-like Pattern" that we have been talking about here and which stands very clearly in the frame.
Latitude (centered): 37,9717° North
Longitude (centered): 78,8752° East
This image (which is an Original Mars Odyssey Orbiter b/w and Map-Projected frame published on the NASA - Planetary Photojournal with the ID n. PIA 18492) has been additionally processed, magnified to aid the visibility of the details, contrast enhanced and sharpened, Gamma corrected and then colorized in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Mars Odyssey Orbiter and then looked down, towards the Surface of Mars), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team.