Charon

Explanation: Artist Mark Garlick's impression of the surface of Charon. "Charon is the largest of the known satellites of Pluto. In this image, we see Charon as it might appear from the surface of Pluto. I imagined the surface to look somewhat like that of Neptune's largest satellite, Triton, though this is of course pure speculation."

Pluto

Image credit: Mark Garlick.