"Into sight 60,000 years of light, fascination with a mountain put to sea. Built to slay and conquer, all with teeth of beasts."
...and built to slay and conquer they were back in the sludge metal era of their career. Now one of the most successful metal bands of the past decade and current one, Mastodon brought back sludge metal in full force at the beginning of the 2000's. While the band has since mellowed out a bit, Mastodon once combined the intensity and pummeling force of Crowbar with the atmospheric brutality of Neurosis. Add in a bit of alternative metal in the vein of Alice in Chains or System of a Down for taste, and you've got yourself Mastodon's classic sound.
Mastodon were a pretty unique band, so these aforementioned influences are mainly just references. The majority of the album is pure raw sludgy brutality, as best exemplified in classics like "Blood and Thunder", "I am Ahab", "Naked Burn", and my personal favorite, "Iron Tusk". The experimental/alternative metal elements come along in the form of plenty of odd time signatures and rapid chromatic riffing that is played in a style akin to SoaD or other bands of similar ilk. This combination of two often separated styles is part of what gave Mastodon such a unique sound when they came out, giving a brutal yet fresh sound during a time when the metal world was still at the end of the reign of generic nu-metal bands (although those would soon be replaced by generic metalcore bands).
The only times the album lets up with the chaotic sludge attack is with the final two tracks, the nearly 14-minute long behemoth "Hearts Alive" and the classical/acoustic guitar ending "Joseph Merrick". These two tracks showcase a more experimental sound in the vein of Neurosis, albeit being more melodious. Speaking of, Neurosis's frontman Scott Kelly makes his first guest appearance on this album as he would on the band's future albums. Other guests include Clutch's Neil Fallon with additional vocals (Blood and Thunder), Matt Bayles on Organ (Joeseph Merrick), and Phil Peterson on Cello (Hearts Alive).
Only their second album, and Mastodon were already in their prime. While the following Blood Mountain is my favorite, both that and Leviathan are up there with the best sludge metal albums and are already considered modern classics. If you want some forceful and sludgy brutality that's a bit more recent than sludge masters like Crowbar and Melvins, the first three Mastodon albums are essential listening. Hope you found this review helpful, feel free to comment!