Mastodon is an American heavy metal band from Atlanta, Georgia, formed in 1999. The band is composed of bassist/vocalist Troy Sanders, guitarist/vocalist Brent Hinds, guitarist Bill Kelliher and drummer/vocalist Brann Dailor. They have released five full-length albums to date, with 2009's Crack the Skye selling 41,000 copies in the United States in its first week of release to land at position No. 11 on The Billboard 200 chart.
Mastodon cross multiple heavy metal genres such as sludge metal, progressive metal, stoner metal, Alternative Metal, and groove metal. Their style has evolved over the years from their earliest work on Remission right through to The Hunter. Many of their songs features heavy and unique instrumentation with a mix of clean vocals and harsh screams. Their four first albums all deal with a special theme respectively Fire, Water, Earth and Air. It is also stated that many of their albums deal with a concept. Scott Kelly of Neurosis has preformed vocals on every Mastodon album excluding Remission.