Source: Lords of Rust, pg(s). 86
Rhu-chaliks, also called void wanderers, are enigmatic minions of the Dominion of the Black that seek out and feed on sentient thought. They can exist comfortably in the void of space, have lifetimes longer that the stars themselves, and can transmit thoughts across the cosmos to the dark masters, making them the perfect scouts.
A single unblinking, pupil-less eye bulges from their black, ovoid bodies, which are typically 3 feet long and composed of about 30 pounds of spongy tissue. From this central mass hang four tendrils coated in a toxic enzyme capable of inflicting excruciating pain. Rhu-chaliks are incredibly deft telepaths, capable of reading thoughts, manipulating memories, and using a target's own fears to shred their sanity. They are even able to duplicate entire minds for transmission back to their Dominion masters.
Scholars suggest that rhu-chaliks did not evolve organically but were selectively bred to suit the exact specifications of their role within the Dominion of the Black.