Korean hip hop group CB Mass, composed of Curbin, Choiza, and Gaeko, originated in Republic of Korea. The trio formed in 1998 after Choiza and Gaeko met Curbin while active in the underground hip hop scene. Prior to forming CB Mass, Choiza and Gaeko were part of an underground hip hop group named Kod with Sixpoint and ZASON. They were also members of the Movement crew, which included pioneers like Tiger JK of Drunken Tiger and members of Uptown and Epik High. CB Mass debuted in 2000 with their first album Massmediah, featuring notable tracks such as "Running" and "For The Club". Their second album, Massmatics released in 2001, achieved significant success with One Hundred Twenty Thousand copies sold in Korea. This album included collaborations with prominent artists like Drunken Tiger and Micki Eyes and featured tracks such as "Movement III" and "New Joint". In 2003, they released their final album Massappeal, which marked the end of their career due to a public dispute involving Curbin's alleged embezzlement of funds. The controversy led to CB Mass disbanding later that year. Following the group's dissolution, Gaeko and Choiza formed Dynamic Duo, while Curbin left the music industry altogether.