Leviathan is the second album by American metal band Mastodon, released in 2004 by Relapse Records. The album is the group's first concept album and is loosely based on the Herman Melville novel Moby-Dick, and the songs "Iron Tusk", "Blood and Thunder", "I Am Ahab" and "Seabeast" were released as singles. Three magazines awarded it Album of the Year in 2004: Revolver, Kerrang! and Terrorizer. In 2009 MetalSucks named Leviathan the best metal album of the 21st century.