Image Cache: These geological features are what NASA refers to as spiders, and they can be found on the surface of Mars.
This image, acquired by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter, shows a 1km-wide view of part of the planet. NASA explains how they form:
[T]hese radial troughs have been refered to as spiders, simply because of their shape. In this region the pattern looks more dendritic as channels branch out numerous times as they get further from the center.
The troughs are believed to be formed by gas flowing beneath the seasonal ice to openings where the gas escapes, carrying along dust from the surface below. The dust falls to the surface of the ice in fan-shaped deposits.
Image by NASA/JPL-Caltech/University of Arizona