Leviathan is the second album by American heavy metal band Mastodon, released in 2004 on Relapse Records. It is Mastodon's first concept album, with lyrics based on the 1851 novel Moby-Dick by Herman Melville. The songs "Iron Tusk", "Naked Burn", and "Blood and Thunder" were released as promotional singles, and music videos were created for "Iron Tusk", "Blood and Thunder", and "Seabeast". Three magazines awarded the album Album of the Year in 2004: Revolver, Kerrang! and Terrorizer. In 2009 and 2015, MetalSucks named Leviathan the best metal album of the 21st century.