Scanning through thousands of images that look exactly the same every single day must be tough. It must be even harder when all those images are of Mars and you're trying to find alien life.
With this in mind then it's not entirely far fetched to think that someone might lose sight of their original goal, start seeing objects where none exist.
It happens from time to time, we look at the object in question, knowingly smile and accept that yes, it looks incredibly similar to a hot dog, but realistically the chances of there being a hot dog on Mars are depressingly slim.
This image is a stark reminder of this phenomenon. It looks a lot like a book, and it's from an official NASA photo. In fact one could say there are some books that look less like books than this rock. Sadly though it is just that, a rock.
The simple truth is however that these are the people who could discover actual alien life, their tireless trawling through libraries of old NASA archive footage will almost inevitably one day result in an alien warrior mask being an actual alien warrior mask. When that happens we'll congratulate them, and then hide.