During the battle between Republic and Separatist forces, TJ-55 led an ambush on the Jedi's forces at the North and South towers of Crystal City. As the remaining Republic forces tried to evacuate from the roof of the South tower, the tactical droid led a squad of B1 battle droids to attack the retreating clone troopers. However, during the fighting, the droid's head was ripped off by clonetrooperGus and was brought back to the Republic's base for a robolobotomy. The investigation only confirmed that there was a spy amongst the Republic's troops before the droid stopped processing. The spy was eventually revealed in the form of Clone SergeantSlick, who was later apprehended.
Consequently, by the time the tactical droid led his forces to the towers, he was well aware of the presence of Republic troops. He commanded his B1 battle droid forces from his Armored Assault Tank and surprised the Jedi and clones by splitting his troops, thus bypassing the ambush. Battle droids then attacked the South tower, where Kenobi was with his troopers. Kenobi and his clones were pinned down by the droids, but Skywalker noticed the situation from the North tower. He signaled an LAAT/i gunship for an evacuation and led his clone troopers to help Kenobi. The Republic forces were able to hold their ground but were forced to retreat with the battle droids' larger numbers. As the Jedi and remaining clones took a turbolift to the roof, where the gunship was landing for evacuation, TJ-55 left his tank and followed the Republic troopers with his droid forces.[2]
On the roof of the South tower, the tactical droid led the attack of the battle droids, in order to prevent the retreat of the Republic troops. Equipped with an E-5 blaster rifle, he managed to shoot at least one clone trooper during the firefight.[2] However, clone trooper Gus[6] saw the tactical droid, jumped for him, ripped his head off, and leaped onto the Republic gunship as it departed from the tower. While the gunship left, the still-functioning body of TJ-55 rotated senselessly, shooting several mis-aimed shots on its own.[2]
Later on at the Republic's Christophsis base, TJ-55's head was analyzed in a robolobotomy by Clone CommanderCC-2224 and Clone CaptainCT-7567. The droid's data files only verified that the Separatists had gained secret information about the positions of the Republic forces before the head stopped processing, ruining any chances of a further analysis. Despite this, the spy was discovered to be Sergeant Slick, who was apprehended,[2] and General Loathsom's droid forces were eventually defeated as well.[7]
―CT-7567, as the head of TJ-55 deactivates after revealing its information — Listen (file info)[src]
TJ-55's head reveals its information.
Like all tactical droids, TJ-55 stood 1.93 meters tall[4] and was far more intelligent than standard battle droids of the Separatist Droid Army and wasn't controlled by a computer, allowing him to think and function independently.[8] In battle, he gave his orders from his Armored Assault Tank, but he was also ready to leave his tank and attack with his troops at close combat range, where he used his E-5 blaster rifle.[2] The droid had the word "TACTICAL" written along the side of his head in Aurebesh,[6] and he also had whitephotoreceptors and masculine programming.[2]
TJ-55 made his first appearance in the Star Wars: The Clone Wars television episode "The Hidden Enemy." He was voiced by James Arnold Taylor, who also provided the voice of Obi-Wan Kenobi and the second tactical droid in the same episode.[6] Even though the droid appeared unnamed in the episode,[2] he was later named as TJ-55 by his concept art, first presented in Star Wars: The Clone Wars: The Complete Season One.[5] The events surrounding the capture of TJ-55's head were also humorously portrayed in the non-canonicalvideo gameLEGO Star Wars III: The Clone Wars, wherein one of the playable characters—Skywalker, Kenobi, CC-2224, or a clone trooper—has to put on the droid's head in order to use a special panel and gain access to the arriving gunship to escape from the South tower's roof.