What sort of mud people/critters made this place?

[Fcsuper]

No bio-signs on the planet, so they are well hidden or long-gone. Creepy place, either way.

 

[DøømHåmstër]

Looks like extinct fumeroles.

 

[Sighman]

Source: https://www.youtube.com/watch?v=krVXRCcr2M4

 

[CMDR Rabbit]

Giant space ants?

 

[FrogsFriend]

Nothing to worry about, just the common or garden Giant Ravenous Space Earthworm.

 

[Bottom Hat]

They are all underground. Those are worm butts sticking up.