The NASA Curiosity rover made headlines last month when it detected a sudden spike of methane gas in the Martian atmosphere, a gas that’s often associated with microbial organisms back on Earth.

The discovery got scientists excited because it might finally answer the question: is there life outside of planet Earth? However, the methane gas dwindled just as fast as it appeared and scientists reasoned that it could have been gas produced by geological reasons.

The methane gas discovery, although exciting, is not the first instance that the Curiosity rover stumbled upon something unique and controversial. Since it landed on the Red Planet back in 2012, the car-sized space vehicle has been sending photos that have “captured” various interesting images that have excited not only the scientific community but alien theorist and UFO enthusiasts as well.

One of them is a photo taken by the Curiosity rover back in 2016 of an image that UFOlogists have regarded as a “sasquatch skull.” According to CNET, the image first appeared in a video posted by YoTube user Paranormal Crucible wherein he enhanced a photo of the surface of the Red Planet.

The odd image showed what looked like cavities for eyes, a nose, an upper jaw and a preserved cranium that looks humanoid but larger. The photo was taken by the Curiosity rover back in May 2016. And some analysts believe that the image caused excitement simply because it was presented in such a compelling way via the video.

However, the rock has been dismissed as simply a rock with an interesting play of shadows. But before that, Paranormal Crucible first declared that it is "obviously alien in nature" and went on to speculate if it is an actual remain of the mythical Sasquatch or simply a "bizarre Martian creature."

The Curiosity rover has been sending back photos of the Martian surface since 2012 and for years, alien theorists have used these images to prove that there might be life on the Red Planet. Some of the photos include “discovering” animals such as monkeys and penguins on the Martian surface. IBTimes even reported seeing the Star Trek logo etched on the dusty floor of Mars.

There was even news of a flying bird that’s said to have been discovered in one of the videos taken by the rover. The image first appeared in a video uploaded by user Sandra Elena Andrade and was picked up by UFO enthusiast or “UFOlogist” Scott Waring of the website ET Database. What’s interesting is that per the alien theorist, the image proved a conspiracy theory that images via NASA’s rover Curiosity were shot, not on the Red Planet but was taken from somewhere on Earth.

Mars rock formation
NASA's Mars rover Curiosity acquired this image using its Mars Hand Lens Imager (MAHLI), located on the turret at the end of the rover's robotic arm, on July 10, 2019, Sol 2462 of the Mars Science Laboratory Mission, at 17:00:31 UTC.When this image was obtained, the focus motor count position was 13531. This number indicates the internal position of the MAHLI lens at the time the image was acquired. This count also tells whether the dust cover was open or closed. Values between 0 and 6000 mean the dust cover was closed; values between 12500 and 16000 occur when the cover is open. For close-up images, the motor count can in some cases be used to estimate the distance between the MAHLI lens and target. For example, in-focus images obtained with the dust cover open for which the lens was 2.5 cm from the target have a motor count near 15270. If the lens is 5 cm from the target, the motor count is near 14360; if 7 cm, 13980; 10 cm, 13635; 15 cm, 13325; 20 cm, 13155; 25 cm, 13050; 30 cm, 12970. These correspond to image scales, in micrometers per pixel, of about 16, 25, 32, 42, 60, 77, 95, and 113.Most images acquired by MAHLI in daylight use the sun as an illumination source. However, in some cases, MAHLI's two groups of white light LEDs and one group of longwave ultraviolet (UV) LEDs might be used to illuminate targets. When Curiosity acquired this image, the group 1 white light LEDs were off, the group 2 white light LEDs were off, and the ultraviolet (UV) LEDS were off. NASA/JPL-Caltech/MSSS