Aartuk
Aartuk are a race of tribal, carnivorous, parasitic plant-monsters native to the Dungeons & Dragons setting of Spelljammer. They worship war, both through various deities and as a concept, and have a bitter enmity with beholders, reputed to be because the beholders destroyed their homeworld.
That's not enough for you? Okay, we'll dig a little deeper...
In terms of appearance, Aartuk are radial symmetrical life forms... or, in layman's terms, they look like giant five-armed starfish. Each arm (branch) bristles with vicious spikes on both its upper and undersides, and has a sucker-like opening near its tip that house three retractable pseudopods; these allow Aartuk to manipulate small objects. In the central body, the upper side conceals an eyespot-rimmed retractable head, which can extend on a prehensile stalk. This "head" contains a mouth-like orifice that is used to deploy a long, sticky "tongue" as well as to spit bullets of sap that hardens into a rock-like solidness upon exposure to the air. In combat, they pepper foes from afar with these biological bullets, or use their tongues to latch onto foes and drag them into range to bludgeon them with their wickedly barbed branches. There are different strains of Aartuk adapted for different environments; known examples include gray specimens who favor sandy or dusty environments; brown-to-gray specimens whose bark has a stony look and who favor rocky terrain; and tribes that favor dense jungles and forests, and who thus let mosses, mushrooms, and other small plants grow on their limbs.
These primitive vegetable life forms live in small, nomadic, tribal societies, centered around their Elders; individual Aartuk who have lived for about 70-90 years and then survived a final growth spurt. These "blossoming" Aartuk develop distinctive growths, resembling things like rocky protrusions, mushrooms or flowers based on the subtype; these Aartuk are known as "Aristocrats" and take up a leadership role, but most die one year after transforming. Those who survive the transformation become Elders and gain a more powerful pellet attack, with twice the range and a new chemical makeup that causes it to burst into flames when used, as well as the ability to cast a number of low-level clerical spells (treat as 4th level with Wisdom 14, in 2e) and to purify stale air (important, because Aartuk need to breathe just like humanoids). Because of this, elder Aartuk are the only Aartuk who can power spelljammers, and this means their tribes depend on them to successfully travel through the Phlogiston. When an Aartuk evolves into an elder, the tribe responds in one of two ways; if they have any ships to spare, the new elder will take the spare ship and leave with a small number of younger Aartuk (and possibly some slaves), otherwise the new elder and the old elder will fight to the death to see who gets to lead the tribe. Upon transforming, an Aartuk will live another 41-60 years before dying.
The Aartuk are best described as religious fanatics who view war as the ultimate form of art; they are one of the many scourges of the frontiers, attacking weaker colonies or isolated ships. Fortunately, their belief in the need to only seek out worthy foes to slay means they will usually spare obviously weak or defenseless targets, instead demanding the possible location of a better fight and often keeping their victims as temporary slave laborers... though they are as likely to kill and eat them once they are done with them as they are to abandon them to (hopefully) be rescued, and they always keep captured pilots to expand their tribe's flotilla. Worthy foes are in for a gruesome end; Aartuks reproduce by infecting living humanoids with spores secreted from their tongue into an open wound, which slowly dissolve a victim into a mass of jelly, from which a new Aartuk will emerge a month later. Aartuk view the "gift of birth", as they call it, as a sign of respect and honor toward a victim, and thus the infection of a suitable victim is conducted as a religious ritual that must be overseen by the tribe's elder.
Aartuk tribes are devoutly religious, but only worship evil war and vengeance gods like Bane, Gruumsh, Hextor or Sargonnas. Their great driving goal is vengeance against all Beholders, for their legends say that the beholder-kin blew up their homeworld and reduced them to scattered bands of nomads wandering wildspace. They are noted to be relatively honorable and prone to keeping their word anyway, so it's implicit that one could use Aartuks as agents against the beholders.
Aartuk do not value precious metals, other than as lures for potential victims. They appreciate gems (their currency), magical weapons, and art pieces related to the topic of war, which they keep as war trophies. Some rare Aartuk magical items with various powers are worn as torques at the base of their head stalks, within the cavity at the center of their bodies. These items may improve Armor Class or grant special abilities common to magical rings (such as invisibility, mind shielding, regeneration, or telekinesis). They are typically reserved for the Aartuk aristocracy and the elders. Humanoids can use Aartuk magical torques, wearing them as arm bracers. Only one such item can be used at a time (wearing two prevents either from functioning). Aartuk cannot use any other type of magical items.
The bodies of Aartuk, either dead or alive, provide no useful components for magic, though the slime on their tongue makes an effective glue when boiled to the appropriate concentration. The tongues may be hung and left to dry for several weeks, which produces an average quality rope. When properly fermented, the sap of elders makes a beverage greatly desired by beholders. An elder provides enough sap to brew a small keg of Aartukia. A shrewd merchant could get several thousand gold pieces for the sale of a single keg.
After 2nd edition, Aartuks largely vanished, but they first received a hint of a mention in Dungeons & Dragons 5th Edition in, of all places, the Forgotten Realms adventure "Waterdeep: Dungeon of the Mad Mage". They finally returned for real in the Spelljammer 5e boxed set as some of the many monsters in Boo's Astral Menagerie. Their lore here is largely a condensation of their old lore, save for dropping the angle about reproducing parasitically. Mechanically, they changed in some weird ways, notably swapping their sap bullets for energy bolts that do radiant damage and losing their clerical magic in favor of psionics.