Harcore hip hop is a form of hip hop music that developed in the late 1980s. Allmusic writes that it is characterized by "confrontation and aggression, whether in the lyrical subject matter, the hard, driving beats, the noisy sampling and production, or any combination thereof." The term can refer to similar musical sensibilities that encompass several related genres, including conscious hip hop, political hip hop, acid rap, abstract hip hop, pornocore, horrorcore, gangsta rap, and alternative hip hop.