Swollen Members are a Canadian hip hop group from Vancouver, British Columbia, Canada consisting principally of the duo Mad Child and Prevail. They have been called "two of the most innovative people in hip-hop". Frequent collaborators include vocalist Moka Only and producer Rob The Viking, an official group member since 2002. Since the group's formation in 1999, Swollen Members has released four studio albums and one compilation, which consists mainly of B-sides as well as three new songs.