Seeing as how the other camera on the rover did not capture this "light" (as seen clearly in this GIF: http://i.imgur.com/LQa9PLU.gif http://i.imgur.com/LQa9PLU

Seeing as how the other camera on the rover did not capture this "light" (as seen clearly in this GIF: http://i.imgur.com/LQa9PLU.gif http://i.imgur.com/LQa9PLU.gif) it seems pretty safe to assume that this is just an artifact caused by a temporary glitch on one of the cameras. Here are the two source images taken at the same time by the rover's two cameras: http://mars.jpl.nasa.gov/msl-raw-images/proj/msl/redops/ods/surface/sol/00589/opgs/edr/ncam/NLB_449790582EDR_F0310000NCAM00262M_.JPG http://mars.jpl.nasa.gov/msl-raw-images/proj/msl/redops/ods/... http://mars.jpl.nasa.gov/msl-raw-images/proj/msl/redops/ods/surface/sol/00589/opgs/edr/ncam/NRB_449790582EDR_F0310000NCAM00262M_.JPG http://mars.jpl.nasa.gov/msl-raw-images/proj/msl/redops/ods/... But of course disreputable "news" sites bring in a UFO enthusiast as their source for a quote about the possibility that there is intelligent life below the surface.