Boomer, an R5 astromech droid, was once the property of Sevox, a human residing on the planet Andelm IV. During a specific undertaking by the human girl Zarro together with the Wookiee Chewbacca, they strategically placed a thermal detonator within the droid, subsequently naming it "Boomer." Their intention was to trigger the detonator while it was aboard a Lambda-class shuttle. The pair succeeded in their scheme, resulting in Boomer's ultimate destruction.
Not long after the Battle of Yavin, Boomer, a discarded R5 astromech droid, found its way into the workshop of the tinkerer Sevox on Andelm IV. Zarro, accompanied by her Wookiee companion Chewbacca, visited Sevox's bunker during a mission to thwart the local gangster Jaum's attempts to export dedlanite to the Galactic Empire. While exploring Sevox's storage area, Chewbacca discovered the derelict R5 unit. Chewbacca successfully repaired the droid, equipping it with multiple thermal detonators before reattaching its head.
Boomer accompanied Zarro and Chewie aboard Jaum's landspeeder to the Andelm IV spaceport. Following Jaum and his droid I-7's departure, the droid and its companions infiltrated the spaceport. Zarro managed to pass the scout troopers stationed outside by impersonating one of Jaum's associates, escorting Chewie, who was disguised as Jaum's newly acquired war droid. Once inside, Zarro's plan was to load Boomer onto a Sentinel-class landing craft carrying Jaum's dedlanite cargo.
However, Jaum intervened, demanding that Zarro remove her helmet. A rapid exchange of gunfire ensued between Chewie and the stormtroopers aiding Jaum. Using a remote control, Zarro directed Boomer up the landing craft's ramp. En route, the droid sustained laser fire and was rendered inoperable. While Chewie battled Jaum's enforcer Tyvak and an All Terrain Scout Transport, Zarro succeeded in pushing Boomer onto the craft. With the droid's remote control system destroyed, she activated a timer and escaped the ship. Jaum, believing he had outsmarted Zarro and Chewie, fled aboard the landing craft, unaware that the bomb-laden Boomer was on board.
Before Zarro and Chewie could leave the spaceport, scout troopers apprehended them and escorted them aboard Commander Kai's Imperial-class Star Destroyer. After subduing their stormtrooper guards, they navigated their way to the Star Destroyer's hangar and secured an audience with Commander Kai. Zarro successfully convinced Kai that Jaum was a deceptive individual and a rebel spy. She further asserted that Jaum had filled Boomer with explosives and placed it on the landing craft docked in the Star Destroyer's hangar. Shortly thereafter, the droid detonated, obliterating the landing craft and causing damage to the Star Destroyer's hangar bay.
Following Boomer's destruction, Zarro and Chewie escaped back to Andelm IV aboard a TIE/sa bomber. Meanwhile, Kai arrested Jaum and subjected him to torture as punishment for the "scam" and the damage inflicted upon his Star Destroyer. Consequently, Boomer played a pivotal role in disrupting Jaum's scheme to establish a dedlanite export business with the Empire and brought an end to Jaum's criminal organization.
Boomer was a malfunctioning R5 repair droid that Chewbacca and Zarro rebuilt for the singular purpose of stopping the gangster Jaum's plot to export dedlanite to the Galactic Empire. It possessed no distinct personality and was remotely controlled by Zarro. Being an astromech droid, it featured a rotating head mounted on a rounded chassis. It also had two wheeled legs. Chewbacca managed to gather enough spare parts from Sevox's storeroom to restore the droid to some level of operational functionality. However, Boomer lacked any independent decision-making ability and was essentially used as a weapon by its new "owners." In its final operational days, Zarro gave the droid the nickname Boomer and equipped it with several explosives.
The initial appearance of Boomer was in Chewbacca (2015) 4, and it was also featured on the cover of that issue.