An image of bizarre "alien" structures heading to the surface of Mars might be exciting enough for UFO enthusiasts. But according to a UFO blog, one picture might just be cause for some extra speculation since it features an "alien skull" on the Red Planet.

Images of the so-called skull, some of which have been digitally altered to prove the specifics, were posted by UFO Sightings Daily on Wednesday. Originally, the images were captured by NASA's Mars Spirit rover at the Gusev Crater.

While most critics will argue that the structure in the image is most likely a rock which somewhat appears to look like a skull in the Martian soil, the blog claims otherwise, even going as far as digitally adding "teeth and [a] lower nostril bone" to show how the specifics could fit in, Epoch Times reported.

"Right away this object in the photo just grabs you. An alien skull with the jaw bone missing or buried below it," the blog posted on Wednesday. "You can make out the nasal cavity and the two eye sockets without any trouble. You can even make out the ridge above the eye sockets."

"It's hard to believe that the rover just passes on by without a second look, but hey, they are not there to discover life, but actually there to distract humanity and show an effort. This way...satisfying human curiosity. Are you...satisfied? I'm not."

The image, which fails to show the other side of the halfway buried object, has been around since 2010. It was first uploaded by a YouTube user, who added his own digital features  later on in a video to make it look like a skull for comparative purposes.

However, observers still remain skeptical.

"The human mind is a curious thing, after hundreds of thousands of years of developing in groups, the first thing even subconsiously, is facial recognition (sic)," wrote one person. "If you allow your mind to wander it's possible to see faces in everything. I can clearly make out a raccoons head also (sic)."