Raggamuffin music, usually abbreviated as ragga, is a sub-genre of dancehall music or reggae, in which the instrumentation primarily consists of electronic music. Sampling often serves a prominent role in raggamuffin music as well.
Wayne Smith's "Under Me Sleng Teng" was produced by King Jammy in 1985 on a Casio MT-40 synthesizer, and is generally recognized as the seminal ragga song. "Sleng Teng" boosted Jammy's popularity immensely, and other producers quickly released their own versions of the riddim, accompanied by dozens of different vocalists.
Ragga is now mainly used as a synonym for dancehall reggae or for describing dancehall with a deejay chatting rather than deejaying or singing on top of the riddim.