Gun is a large hand gun with an advanced targeting system, artificial intelligence control system, and multiple firing options. Matrix found Gun at some point during his travels through the Game Cubes. Matrix had been injured in the Gods, Mortals, and Demons Game by the User, losing his right eye from the injury. Eventually he had a metallic implant installed to replace his eye. The implant was linked to Gun so that he could track and lock onto his targets.
When Gun targets something or someone it releases harmless red crosshairs that affix themselves to the targets. Then Matrix's implant keeps track of the red targets. By giving commands to Gun it will release the targets, start special firing patterns, and even fire itself when told to. Gun can also be fired manually without something having a target lock on it. When not in use, Gun attaches itself to the side of Matrix's leg.
Matrix went into the Web with the crew of the Saucy Mare and the surfer Ray Tracer. When he was forced to leave the safety of the ship to chase a Web Creature he left Gun with Captain Capacitor because it would degrade in the hostile environment of the Web. Later the Web Riders attacked the ship and Matrix pushed Gun's barrel through the ship's Web shields so that he could target the Riders and help defend the ship. After he scared the Riders off and removed the barrel from the shields the end of Gun was smoking from the close contact with the Web. (Web Riders on the Storm)
Matrix eventually returned to Mainframe and helped the Mainframe rebellion to bring down Megabyte. When he finally confronted the virus, Megabyte tricked Matrix into putting down Gun and 'fighting like a real sprite'. Matrix dropped Gun and hit Megabyte hard in the chest. The virus didn't live up to this little agreement after all, using his long retractable claws, although AndrAIa responded to this by giving Matrix her trident, with which he was able to shatter Megabyte's claws and defeat him. Megabyte attempted to escape to the Net, but was thwarted when Mouse redirected him to the Web at the last second. (Showdown)
Mouse and Matrix couldn't stand sitting still just waiting in Mainframe while Daemon's infection grew. They decided to take matters into their own hands and flew to the Super Computer to assassinate Daemon before she managed to breach Mainframe's defenses. When they arrived Matrix walked into the dark throne room and had Gun target the person sitting on the throne. The lights came up and revealed it was the infected AndrAIa. They ran to each other and then AndrAIa turned to introduce Matrix to Daemon, who was hovering over the throne. Matrix quickly drew Gun and fired a bullet with Daemon's name on it. The time speed altering affects of the throne room slowed the bullet down until it stopped in front of Daemon. She took the bullet in her hand and it exploded, then reassembled, and she blew on it, causing it to crumble into dust. She informed him that his weapon was useless. (What's Love Got To Do With It?)
At Dot Matrix's failed wedding, Matrix left Gun at Dot's Diner. He decided for once that he wouldn't need it. This did prove false when the second Bob turned out to be Megabyte in disguise. Matrix was little help in the short fight that followed since he didn't have Gun with him.
In a plan to capture Megabyte, Matrix had Gun target the virus, enabling them to see him, no matter what binome he turned into, in turn allowing Bob to portal him to prison.
- Gun resembles a submachine gun, notably a Skorpion vz.61 smg.
- During his time in the Desert Port System, Matrix gave Gun the command "Death Blossom Mode", which caused Gun to rapidly spin on all its axes. This could be a direct reference to The Last Starfighter, in which Death Blossom was a special weapon mode used to target and eliminate multiple ships in all directions.