"Disco Gun" is a term devised by online communities for an unusual editing technique used for the American broadcast of the anime series Mobile Suit Gundam SEED in which distracting neon lights are painted on firearms to make them appear to be unrealistic weapons. The first one, held by Andrew Waltfeld, appeared in episode 19 to much surprise from fans. While the series had quite heavily edited up until that point, guns normally had their sound effects toned down to sound more "futuristic". In this case, however, a troublesome situation occured in which a gun was being pointed directly at an underaged character. Despite the fact that the character was a soldier fighting in a war situation and the gun was never actually intended to be fired at him, William's Street was ordered to either alter the gun or cut the scene. In episode 42 of Gundam SEED this technique was used again when Patrick Zala aimed a gun at his son Athrun. But when episode 49 of Gundam SEED aired on Cartoon Network, Murata Azraels gun for most of the episode didn't have any edits to it. But near the end of the episode after he shot Natarle Badgiruel once it was shown in it's edited form. It is unknown if that was due to bad editing or if it was intentional.
Based on the fact that edited guns in the series Outlaw Star looked much more plausable, some believe that the disco guns were done at the last minute and intentionally made to look ridiculous so that the edits would be obvious to viewers. Whatever the case, this became a trend as the series went on, with virtually every gun in the show being altered merely for the sake of continuity and, likely, stricter watchdog censorship from Tuner's BS&P division. In one particular case, laser beams were also painted in as two characters fired at eachother. The term "[this character] got DISCO'D" became a popular catchphrase.
It should be pointed out that previous Gundam series' had run with no similar edits.