“Isolated Araneiform Topography”
This image of the south pole was taken by HiRISE on (87.123°S, 126.291°E) on March 24th, 2007. Araneiform comes “aranea” (Latin) meaning spider; the HiRISE team saw these channels, carved into the surface by CO2 gas erupting from the ground, and thought they looked spider-like. They form after CO2 sublimates as the seasons change causing a build up a gas below the surface. Eventually the surface ruptures, creating these features. To me they look more like neurons but I can see their resemblence to spiders.
The width of this image is about 1 km.
Credit: NASA/JPL/University of Arizona