Mastodon's musical style has evolved much from their earliest pre-"Remission" releases to "The Hunter". Their early work is significantly heavier and more abrasive than their later work, primarily or exclusively using harsh vocals, more distorted instruments, and more atypical song structures; this is especially prominent in their earliest work. The release of Mastodon's third studio album, "Blood Mountain", which incorporates both clean and harsh vocals, marked a shift in the vocal styles used, with subsequent albums favouring clean vocals almost exclusively.