What One Becomes is the second album by Sumac, a trio led by Aaron Turner, formerly of Isis. Sumac's sound is somewhere between brutal sludge metal and chaotic experimental noise rock, with harsh, guttural growls and scorching guitars accompanied by explosive drumming. When the rhythms are steady, they're often slow and hammering, but they never stay in the same place for long. Drummer Nick Yacyshyn constantly plays complicated fills, frequently elevating to free jazz-like chaos, and the tempos change often within each track. Brian Cook (of Russian Circles and formerly Botch, These Arms Are Snakes, and others) anchors everything with his thick, pulverizing bass. All five songs hover around the ten-minute mark (with "Blackout" exceeding 17), and they go through several movements, often stopping for ambient interludes before launching into what seems like another song entirely. Both "Rigid Man" and "Will to Reach" pause to breathe midway, crawling back into a more atmospheric state before building up to a harsh, pummeling climax. Turner's lyrics aren't easy to discern without the lyric sheet (which is included with the physical release of the album), but they deal with personal anxiety and issues regarding identity, and he delivers them with an appropriate level of frustration and venom. The album is an intense, unpredictable experience, but it seems to progress naturally, and it never feels like they're throwing in esoteric parts just to show off their technical abilities. It's challenging and confrontational, but it's still engaging and relatable. Bracing and personal, What One Becomes is some of Turner's most intense work yet.