i do not believe it to be anything alive, for there is two pictures now and they both in same position. however i dont think its just a shadow cause there is far too much detail behind it. What i think maybe a possibility, there may have been life on mars at one time, like what we have here, they may have had water, air, and a ozone layer like we do. If that would be the case then we could be looking at a statue that was built, and life on mars could have gotten destroyed by their ozone layer decapitating... much like ours is.