I lost some interest in supposed evidence for alien life, whether fossilised or extant, on Mars, after the same official explanation was given every time.
Namely that, due to Mars' lower gravity and minimal weather conditions, erosion on the Red Planet will produce some seemingly strange shapes that would be too fragile to survive on Earth.
Still, it would have been nice if the Curiosity Rover had shuffled over for a closer look at these two objects with protuberances resembling arthropod legs and the various stick-like objects protruding from and casting shadows on the sand (one looks just like the long ladle I used when brewing beer!). It's hard to imagine the kind of specialised erosion that could carve out structures like these.
Finally, a shame that no Mars lander has been anywhere near the evocative tree-like objects, as photographed by the orbiter and which the late Arthur C Clarke suspected were genuine plant life.