NASA shares creepy image of 'spiders' on Mars

this image from NASA's Mars Reconnaissance Orbiter, acquired May 13, 2018 during winter at the South Pole of Mars, shows a carbon dioxide ice cap covering the region and as the sun returns in the spring, "spiders" begin to emerge from the landscape. (Credit: NASA/JPL-Caltech/Univ. of Arizona)

Arachnophobia is defined as the "extreme or irrational fear of spiders." But that "fear" isn't just limited to Earth.

NASA shared a creepy image of Mars on Thursday, showing "'spiders' begin to emerge from the landscape" from the South Pole of Mars. The spiders are not actually eight-legged arachnids, though.

In fact, the "spiders" seen in the image are actually "araneiform terrain," which NASA describes as "spider-like radiating mounds that form when carbon dioxide ice below the surface heats up and releases."

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The government space agency noted that the process is not found here on Earth and is caused when carbon dioxide ice turns from a solid into a gas. The gas then builds up under the surface and ultimately breaks through in jets that deposit a darker dust around the planet.

"The loss of the sublimated carbon dioxide leaves behind these spider-like features etched into the surface," NASA explained on its website.

The image was taken by the Mars Reconnaissance Orbiter on May 13, 2018, during Mars' winter season.

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