The stilt-legged spiderdroid-like automatons had large balloon-like heads atop their thin stalk bodies, armed with laser turrets, rocket launchers, flamethrowers, or chain-fed ordnance launchers. The reserves of ammunition stored within the hollows of its bulbous head. They were named after the eight-eyed, gasbag-headed vine walkers native to Skako. They were equipped with three laser turrets as standard, one on each side, below each photoreceptor. A certain variant was filled with a gaseous virus that would be released upon the droid's destruction, which was highly effective against organic enemy troops. These virus variants were nicknamed "virus droids", but they were not widely used, because many leader personalities of the CIS were also humanoids, so the virus could kill them too. One rocket fired from a single behemoth was powerful enough to annihilate a UT-AT if aimed correctly, as seen in the Battle of Mygeeto. These three-legged artillery droids were formidable in battle, reducing infantry and tanks to rubble. Their rotating multi-jointed assemblies allowed them to change facing almost instantly and they could fire from extended ranges. It could fire almost constantly. The tridroid fired with the first cannon, then rotated its head with 120 degrees. The second cannon locked on target, while the first got ammo from the head. After the second cannon shot, rotated 120 degrees again, and the third cannon fired, while the second was reloaded. When the third finished, the first came again, and it could do this until eternity, until the ammo was depleted, or until the droid has been destroyed. So these CIS droids were formidable artillery units in battle, it was almost impossible to approach such droids, as all sides conceivably faced the front. Though they were vulnerable in close-quarters fighting, or if they were attacked from above. This tactic could be seen in the Clone Wars pilot episode, when Anakin and a squad of his jettroopers attacked from above from the top of a building, Anakin climbed on a droid, while the troops ran under it, constantly firing its vulnerable bottom regions.

On the planet Christophsis, many tri-droids saw action under the command of Whorm Loathsom alongside Tank Droids and AATs, covered in blue markings of the Confederacy of Independent Systems. It was a routine, all second generation vehicles, or droids were repainted, changing the original Techno Union, or Trade Federation colors into blue white. The droid was also capable of hanging onto vertical surfaces, as seen during the Battle of Christophsis. Prior to the battle, Asajj Ventress used one of the droids to escape from Generals Kenobi and Skywalker. The droid was destroyed when it crashed to the ground from the building it was clung to, thanks to the 2 Jedi severing it's limbs. Octuptarra tri-droids also saw action during the Battle of Utapau, where they protected General Grievous' headquarters, and near the end of the Clone Wars, during the Battle of Mygeeto, tri-droids were used against Jedi Master Ki-Adi-Mundi's Galactic Marines, decimating front lines. But they could be seen in the Clone Wars cartoon, too. During the Battle of Coruscant, a group of octuptarra tri-droids used their laser beam cannons against Jedi Masters Mace Windu and Yoda. The beams could be maintained, similar to the OG-9 homing spider droid's turret, so the Jedi were able to destroy several tri-droids with one beam by deflecting it with their lightsabers. When the battle was over, the remains of the droids fell into the Coruscant underlevels, where strains of the virus leaked out and caused an unfortunate outbreak of moulting in the city's numerous avian species.