Rathtars were substantial, flesh-eating cephalopod creatures that originated on the planet of Twon Ketee, their homeworld. These beasts, considered among the most perilous in the galaxy, were notorious for hunting collaboratively. A particularly infamous event, the Trillia Massacre, involved their subspecies, the dwarf rathtar. Genetically, they shared a lineage with the sarlacc, blixus, and vixus. Their diet was carnivorous.
Despite the inherent risks that made rathtar study uncommon, it was posited that they had a common heritage with other tentacled species, including the sarlaccs, blixii, and vixus native to Umbara. Rathtars reproduced through fission, which could lead to rapid population growth if unchecked. A group of rathtars was collectively referred to as a "remorse".
Hailing from Twon Ketee, rathtars presented as physiologically simple organisms, equipped with limited sensory capabilities and small brains. However, despite seeming like simple eating machines, rathtars were adept at coordinated action and demonstrated a propensity for group hunting. Individual rathtars appeared to gain intelligence when near others of their kind, and rathtar packs employed howls, inaudible to humanoids, for communication. They also produced loud roars during attacks and consumption, and emitted piercing shrieks when injured. The best survival strategy against a rathtar was concealment, given their significant blindness.
A rathtar, lacking a genuine skeleton, possessed a massive, spherical, slug-like body covered with light-sensitive orbs. It featured numerous elongated, tentacle-like limbs; the primary feeding tentacles lashed out to seize and devour prey, typically anything identified as non-rathtar. Voracious and relentless eaters, these creatures could ingest nearly anything that fit into their sturdy, radial mouths, which were funnel-shaped and armed with rows of exceedingly sharp teeth. Their throats expanded into a hollow tongue, facilitating the swallowing of struggling prey. These creatures often dismembered their meals.
Rathtars were capable of movement, curling their tentacles inward to form a sphere and propelling themselves forward in a flurry of whipping appendages. Despite their size, they moved surprisingly quickly and possessed adhesive pads on their pointed tentacle tips—referred to as a club—allowing them to adhere to surfaces. Their tentacles were immensely strong, constructed in a muscular hydrostat configuration. Their fleshy bodies were encased in a tough, rubbery hide, granting rathtars substantial resistance to blaster fire, small arms, and even biting.
A smaller subspecies of rathtar, the dwarf rathtar, was found on Trillia.
The perilous nature of rathtars made their biological study exceedingly rare. Despite the extreme difficulty of capturing even a single rathtar, their dangerous reputation made them targets for hunters and collectors. More often than not, however, rathtar hunters became the hunted. Among the exclusive clientele seeking smuggled rathtars were those who collected live biological specimens, particularly valuing live rathtars. Notable among these were King Prana and his rival, Regent Solculvis of the Mol'leaj system.
During the Nihil's attack on Starlight Beacon, Nihil infiltrators gained access to the space station disguised as cargo ships carrying rathtars. In reality, only one ship contained rathtars, while the others held the Nihil marauder's equipment and several Nameless creatures. Later, as Starlight Beacon descended into the atmosphere of Eiram, the Jedi Padawans Burryaga Agaburry and Bell Zettifar released the rathtars onto the collapsing station. Although the Jedi managed to fight back and eliminate several of the creatures, the three remaining rathtars escaped. Subsequently, Agaburry seemingly sacrificed himself to the two remaining rathtars to protect Elzar Mann and the civilians in the main cargo bay.
On Twon Ketee, during the final decades of the Galactic Republic, a big-game hunter employed a team to hunt them. Led by an alien hunter, the group encountered a rathtar in the swamps, which used its tentacles to slam the hunters into solid objects before consuming them. Darth Maul, a Sith Lord, observed the massacre and attacked the rathtar with an axe. After defeating it, he realized they were pack hunters and confronted two more. Maul indulged his bloodlust by killing both, dropping a tree on the last, and left the planet to report to his Sith Master, Darth Sidious.
Early in the Galactic Empire's reign, a rathtar was caged in the Lau cargo docks. During a clash, Captain Mann sought cover beside the rathtar's cage and unlocked it. To his dismay, the creature seized him with its tentacles and dragged him inside as he desperately tried to escape by grabbing the partially opened doors, only for them to close. He screamed as the rathtar devoured him alive.
Before his involvement in the Dragon Void Run, Han Solo attempted to pilfer a newly hatched rathtar belonging to the alien Dorae, who intended to use it to settle debts. The beast tried to eat Solo, prompting his Wookiee First Mate Chewbacca to kill it. Unable to pay her debts, Dorae lost her protection and suffered greatly. During the Galactic Civil War, she sought out Solo and Chewbacca, seeking retribution for her misfortunes.
Before the Cold War, rathtars were implicated in the Trillia Massacre, a horrific event where many beings were killed and consumed by dwarf rathtars. Three decades after the Battle of Endor, Han Solo was transporting three rathtars aboard his Baleen-class heavy freighter, the Eravana, although acquiring the creatures cost Solo most of his crew. Solo was transporting them to King Prana, a collector supposedly in competition with the regent of the Mol'leaj system. When Han, Chewbacca, and BB-8 were confronted by Kanjiklub and the Guavian Death Gang, Rey and Finn listened from below. As Han appeared to be in danger, Rey suggested sealing the blast doors on either side by resetting the fuses. Unfortunately, Rey tampered with the wrong fuses, unleashing the rathtars, whose terrifying cries echoed throughout the freighter. Just as the combined gangsters of Kanjiklub and the Guavian Death Gang were about to kill Han and Chewie, both groups were suddenly attacked from behind by two of the rathtars, while the third chased Finn and Rey throughout the ship. A rathtar grabbed Finn and almost ate him, but Rey saved him by closing a door on the tentacle holding Finn.
As Rey, Finn, and Solo escaped aboard the Millennium Falcon, a rathtar latched onto the cockpit window, attempting to bite through it. The Falcon jumped into hyperspace with the rathtar still attached, and the extreme acceleration tore it apart, leaving smears on the window. Several rathtars survived aboard the Eravana, and King Prana eventually learned of the incident, displeased at being denied his prizes.
Rathtars debuted in the 2015 film Star Wars: Episode VII The Force Awakens, the initial entry in the Star Wars sequel trilogy. According to director J.J. Abrams, their design aimed for "family-scary" rather than genuinely frightening, to create an enjoyable alien horror scene.