Before some time I pointed to the possible alien life regarding elongated artifact at this official photo of Rosetta mission. It apparently casts shadow (so it's not detector chip or cosmic ray artifact or something similar) and it resembles plant or fungus trying to stand upright on inclined surface because of gravitropism . The end of "plant" stem looks thicker, like this one holding succulent leaves, inflorescence or sporangium. It looks quite unnaturally in the comet environment.