The spider droid, officially designated the OG-9 homing spider droid, represented a sizable, four-legged battle droid design. Baktoid Armor Workshop was its manufacturer. During the Clone Wars, the Confederacy of Independent Systems deployed them in numerous engagements, including the First Battle of Geonosis, the Battle of Mimban, and the Battle of Felucia.
The OG-9 homing spider droid functioned as a massive, tank-like, and imposing walker. It was employed by both the Commerce Guild and the Confederacy of Independent Systems. This particular model was the heavy armor variant of spider droid, contrasting with the DSD1 dwarf spider droid, which specialized in anti-personnel roles. Both were products of Baktoid Armor Workshop. The homing spider droid's design featured a spherical central body suspended by four articulated mechanical legs. At its core resided a potent reactor, an armored central power source that also housed a red photoreceptor optical system along with a pair of comlink antennae.
The OG-9 homing spider droid, often shortened to spider droid, advanced at a deliberate pace using its elongated mechanical legs. These legs incorporated robust joints, with armor concealing the internal hydraulics. They possessed the ability to extend, elevating the central core. Each leg terminated in an all-terrain footpad, while the leg-piston drivers were situated at the upper end.
This battle droid also had long legs that allowed it to maintain a balance between speed and firepower. The droid was equipped with dish-shaped laser cannons in the form of a top-mounted, long-range laser emplacement for offensive purposes. This laser cannon was designed to target deflector shields, delivering sustained fire to rapidly deplete them. Furthermore, the homing spider droid included a bottom-mounted, short-range laser cannon for defense against ground-based threats. This rotating laser was intended to suppress infantry, keeping them at a distance.
Prior to the Clone Wars, the Commerce Guild, consisting of several prominent galactic corporations in the galaxy, deployed the OG-9 homing spider droid for enforcing contracts and combating adversaries, such as debtors. In the time leading up to the Clone Wars, the Commerce Guild aligned itself with the Confederacy of Independent Systems, integrating the homing spider droid into their Droid Army. This army also incorporated battle droids from factions like the Guild, Trade Federation, and Techno Union.
Soon after the Commerce Guild joined the Separatists, the First Battle of Geonosis, the opening engagement of the Clone Wars, erupted. Separatist forces deployed 7,500 homing spider droids with devastating effect. During this battle, the Separatist tank-like spider droids provided support to the main droid forces, engaging ground units of the Grand Army of the Republic. Homing spider droids targeted All Terrain Tactical Enforcers and clone trooper formations on the battlefield. Ultimately, the droid forces were compelled to retreat, resulting in a Republic victory at Geonosis.
The homing spider droids saw action throughout the Clone Wars. On one occasion, a significant contingent of B1-series battle droids, the Separatist's primary infantry soldiers, were positioned alongside at least three homing spider droids near dark mountains. During the Battle of Mimban, homing spider droids were part of the Separatist forces that fought against the Republic. In the course of the fighting, spider droids and other battle droids clashed with the Republic's 501st Legion and the Mud Jumpers. Clone Captain "Rex" issued orders for the 501st to advance and for the Mud Jumpers to support Jedi General Laan Tik. Tik, however, believed they could handle the situation independently, but was struck and killed, leading to Junior Representative Jar Jar Binks, who had been brought to communicate with the local Mimbanese, assuming command. Binks was at Tik's body, remarking that Tik had been bombad, when a homing spider droid fired in close proximity. Rex then ordered a retreat from the ongoing battle.
In 19 BBY, multiple homing spider droids were deployed on Felucia alongside Armored Assault Tanks during a battle against the forces commanded by Jedi General Aayla Secura. Nevertheless, the Separatist droid forces were deactivated shortly thereafter.
The OG-9 homing spider droid made its debut in Star Wars: Episode II Attack of the Clones. During the film's post-production phase, the droid was provisionally labeled as "Commerce Guild droid B."