Rapid 99 are a rival gang in Jet Set Radio Future. They are first encountered the first time you go to 99th Street. Their former leader was Cube until she left to lead Poison Jam, making the two gangs bitter rivals. Rapid 99 will give the player the location of Poison's Jam's hideout if the player can beat Rapid 99 in a game of Capture the Flag around 99th Street. According to the official JSRF website, Rapid 99 were originally a punk rock band called Rapid but their music wasn't popular so they disbanded and formed a gang instead. They then took over 99th Street which led to them changing their name to Rapid 99.

Jet Set Radio
Jet Set Radio is a 2000 action video game developed by Smilebit and published by Sega for the Dreamcast. The player controls a member of a youth gang, the GGs, as they use inline skates to traverse Tokyo, spraying graffiti and evading authorities. Development was headed by director Masayoshi Kikuchi, with art by Ryuta Ueda. Influence was drawn from late 90s Japanese pop culture such as the rhythm game PaRappa the Rapper, and the anti-establishment themes in the film Fight Club. The environments were based on Tokyo shopping districts in Shibuya and Shinjuku, with graffiti designed by artists including Eric Haze. It was the first game to use a cel-shaded art style, developed in response to the team's disappointment towards Sega games mainly resembling anime or manga. Jet Set Radio received acclaim for its graphics, soundtrack, and gameplay. It won several awards and was nominated for many others. A Game Boy Advance version, developed by Vicarious Visions, was released in 2003, along with versions for Japanese mobile phones. In 2012, Jet Set Radio was digitally re-released for the Xbox 360, PlayStation 3 and iOS, followed by releases for Windows, PlayStation Vita and Android. A sequel, Jet Set Radio Future, was released for the Xbox in 2002.