Over the course of the 21 years that led them to sixth full-length Head Cage, Virginia's extreme music institution Pig Destroyer slowly evolved. Beginning in a fertile era of scuzzy D.I.Y. hardcore culture, the earliest iterations of the band were dedicated to frenzied grindcore blasts; songs that rarely lasted more than a minute and called up as much political angst in the lyrics as they did brutally fantastical imagery. A sound defined by the absence of a bassist grew to include more sound samples, more deeply considered arrangements, and noise-informed electronics as the years grew. 2001's grim masterpiece Prowler in the Yard was an introduction to the band for many fans, but in the decade that followed, they moved into unexpected territory and redefined their sound slightly with each new release. Head Cage is the band's first full-length outing since 2012's Book Burner and the first ever to include bass guitar, played by John Jarvis. A far cry from the lo-fi blastbeat frenzy they built their sound on, Head Cage is another evolution for the band, deliberately moving in increments toward new levels of extreme expression. Always fans of eerie intros, the band begins the record with warped '20s jazz before erupting into squalls of noise, leading into the bombast of "Dark Train," a thrashed-out beast that almost gets into metalcore territory but stops abruptly and melts into white noise. Lead single "Army of Cops" continues the exploration of new sounds, driven by a distorted bass riff and sounding more like high-energy punk with metal tendencies than the unfiltered grindcore that Pig Destroyer made their name on. That said, lava-hot blasts like "Terminal Itch" aren't too far removed from the screaming grind that earlier versions of the band traded in. Tracks like this and "Trap Door Man" call on some of the band's trademark intensity, but the addition of bass allows for the moments of groove and midtempo heaviness to interrupt the more disorienting segments of the album. All these various impulses come to a head in the last two tracks, with penultimate song "The Last Song" moving from a nasty noise/funk intro into Slayer-esque power riffing and a pummeling coda of double-bass trash-metal chugging. Seven-minute album-closer "House of Snakes" winds long, near-ambient guitar harmonies into a raw dirgy sludge metal monolith that makes great use of the newly added bass element. Unrelentingly harsh and moving deliberately away from previously charted territory, Head Cage might disappoint fans looking for a rehash of former styles and statements, but those excited by Pig Destroyer's journey through new forms of despair and hostility will enjoy hearing their hybrid sound continue to mutate. ~ Fred Thomas, Rovi

1		Tunnel Under the Tracks
2		Dark Train
3		Army of Cops
4		Circle River
5		The Torture Fields
6		Terminal Itch
7		Concrete Beast
8		The Adventures of Jason and Jr
9		Mt. Skull
10		Trap Door Man
11		The Last Song
12		House of Snakes