Sleep is an American stoner metal band formed in 1990 in Los Angeles, consisting of drummer Chris Hakius, guitarist Al Cisneros, and vocalist Matt Pike. The band is best known for their 1992 album 'Dragonaut' and their 1996 landmark album 'Dopesmoker', which is considered a classic of the stoner metal genre and features extended, heavy riffs with a psychedelic influence. After disbanding in the early 2000s, Sleep reunited in 2009 and has continued performing and recording.