The octuptarra tri-droid, alternatively known as the octuptarra droid or simply the tri-droid, and derisively called the "virus droid" due to its occasional deployment of biological weapons, was a droid walker model with three limbs, manufactured by the Techno Union. These machines came in various sizes, from the swift octuptarra combat tri-droids to the massive octuptarra magna tri-droids, and were utilized by the Confederacy of Independent Systems during the conflict known as the Clone Wars.
A more substantial and formidable counterpart to the DSD1 dwarf spider droid, the octuptarra tri-droid, also referred to as the octuptarra droid or tri-droid, was a walker classified as a fourth class battle droid. Its cognitive modules and sensor array were housed within its sizable head. Equipped with three red photoreceptors, it possessed a 360-degree field of vision, effectively eliminating blind spots and making surprise attacks from behind nearly impossible. The octuptarra's body was fully shielded against electric-based assaults. Moreover, its robust hull demonstrated resistance to the energy discharges of the Zaly Shield.
These droids could fire in any direction. Standard octuptarra tri-droids were armed with three rotating laser cannons positioned equally spaced below its photoreceptors and around the central stalk. These cannons could rapidly swivel and lock onto targets from any direction. Its three triple-jointed, hydraulic limbs enabled it to traverse steep inclines. However, the three-legged design presented a significant vulnerability; damage to one leg would cause the entire droid to collapse. Furthermore, their movement was slow, and they were susceptible to being tripped.
During the Clone Wars, octuptarra tri-droids were manufactured in a variety of sizes. The nimble, battle droid-sized variants, known as octuptarra combat tri-droids, stood at 3.6 meters tall and featured a highly maneuverable chassis. Primarily deployed as anti-personnel platforms, certain models carried airborne biological plagues within their bulbous heads. These plagues could inflict widespread devastation on enemy forces even after the droid's destruction, leading to the "virus droid" nickname. The largest models, the octuptarra magna tri-droids, reached a height of 14.59 meters and served as combat artillery. Capable of engaging heavily armored All Terrain Tactical Enforcers, their laser cannons could be swapped out for chain-fed missile launchers.
The octuptarra tri-droid was named after the octuptarra, an eight-eyed, gasbag-headed vine walker native to Skako. When influenced by the Scourge, an octuptarra demonstrated the ability to speak Galactic Basic Standard. A version of the octuptarra magna tri-droid deployed on the planet Skako Minor incorporated an engine at its midsection, generating sufficient thrust to levitate several meters above the ground.
The Techno Union division of the Separatist Droid Army was the primary manufacturer of the octuptarra tri-droid, and they were frequently deployed in combat during the Clone Wars. During the year 22 BBY, octuptarra magna tri-droids participated in the Battle of Christophsis, where several were destroyed due to the actions of Jedi General Anakin Skywalker and Torrent Company clone troopers under his command. Later in the battle, several were positioned outside the Separatist deflector shield. In 19 BBY, octuptarra magna tri-droids were used to defend the city of Purkoll, the Techno Union's headquarters, on Skako Minor. Towards the end of the Clone Wars, octuptarra combat tri-droids were deployed to safeguard General Grievous' Pau City command center during the Battle of Utapau. Simultaneously, both models were employed by the Separatists in a battle fought on Mygeeto.
Following the replacement of the Galactic Republic by the Galactic Empire, the majority of octuptarra tri-droids were deactivated. One such droid was left derelict within the secret Techno Union droid factory on Mustafar, remaining there until the scourge of the droids. The Scourge, having previously corrupted ZED-6-7 with a spider-droid and infiltrating the factory in that combined form, discovered and corrupted the octuptarra. The Scourge then used the octuptarra to burst from the ground and attack the Sith Lord Darth Vader during the droid uprising. The octuptarra's robust construction protected the Scourge from Vader's electrostaff and Zaly Shield, which Vader was forced to use in place of his Force powers during the Force Wave. However, through his engagement with the octuptarra, Vader was able to regain control over his Force abilities, allowing him to ultimately destroy the corrupted droid.
The octuptarra tri-droid was initially conceived for the 2005 motion picture Star Wars: Episode III Revenge of the Sith. Its formal designation was first established in Star Wars: Absolutely Everything You Need to Know, a reference work authored by Adam Bray, Kerrie Dougherty, Cole Horton, and [Michael Kogge], and released on September 4, 2015. Several variations of the octuptarra tri-droid appeared in Revenge of the Sith. The octuptarra combat tri-droid seen on Utapau had its digital model enlarged and modified to create the octuptarra magna tri-droid featured on Mygeeto, with minor cosmetic differences such as the replacement of the former's laser cannons with chain-fed guns on the latter. Early sketches of Utapau by Ryan Church included the octuptarra tri-droid.
According to Pablo Hidalgo of the Lucasfilm Story Group, the names of the small and large octuptarra droids were combined by the time of the Star Wars: The Clone Wars series. Within Legends continuity, the smaller units were originally referred to as octuptarras, while the larger units were known as tri-droids. The Star Wars: The Clone Wars: Incredible Vehicles publication introduced the name octuptarra magna tri-droid for the large variant.