The European Space Agency’s Mars Express orbiter has spotted “spiders” on the Red Planet’s southern polar region.

But they’re not the arachnids we fear or adore back on Earth — they’re the result of a complex geological process that causes carbon dioxide to sublimate, digging up darker material from below the surface during the planet’s spring.

And they’re a whole lot larger than the spiders you’re used to, measuring up to 3,300 feet across.

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Many of these spots have been found outside of a Martian landscape dubbed Inca City (formally Angustus Labyrinthus) thanks to its geometric ridges that summon to mind Inca ruins.