DoxumCaveat emptor
Styx
Doxum (Caveat emptor, "let the buyer beware"; common name from Leucochloridium paradoxum) are Styx that resemble Tellusian green-banded broodsacs (parasitic flatworms).
This parasitic Styx has an unabating appetite for Stardust, making Starlyngs their ideal host (they cannot—strangely enough—parasitize Oort or Boötes). If not removed in a timely manner, Doxum can hijack a Starlyng's ability to shapeshift and completely alter their visage. The emergent qualities of Doxum can vary wildly in both appearance and extent; some may (choose to) not present visibly.
Doxum appear to exhibit a degree of "tunnel vision" and care for little more than satiating their ceaseless hunger. They have been known to consume other, Stardust-rich Styx, including fellow Doxum. During "brief moments of lucidity", Doxum have showcased signs of complex intelligence. They have a strangely romantic and somewhat prosey, Morse code-esque communication style, and will often use their bodies to "gesticulate" during conversation (many will shape themselves after Humi-esque letters).
Artwork by lycoris