Sometimes it seems that there are people who are willing to explore the Martian each picture under the microscope, just to find something that will resemble the familiar things. And sometimes they get it. I offer you a photo collection, in frames of which were found the skull on Mars.
This photo was submitted rover Spirit
The detailed examination of another photo
This is the photo sent by Curiosity
The influence of climate on Mars rocks, or is it something else? One will find the answer for himself.