Like one of those alien-looking fish creatures that inhabit the most unfathomable marine abyss, Oceano's aptly named debut album, 2009's Depths, embodies a frightening musical mutation, taking otherwise familiar extreme metal genres and then twisting them into shapes quite unnatural to this mortal coil. Ironically, the quintet hails from Chicago of all places, nearly a thousand miles from the nearest seashore, so perhaps their name was chosen exactly because it illustrates the world-spanning, interconnected musical currents that continually clash, combine, and the crash upon the sands of their imagination -- like turbulent tsunamis of sound. Primarily, those influences entail generous doses of grindcore and death metal that, under normal circumstances, might produce the sort of moderately accessible deathcore blend quite prevalent in the waning years of the third millennium's first decade. But Oceano quickly scuttle any semblance of commercialism with the sheer magnitude of the churning, down-tuned riffs and guttural croaks adorning their songs. Also, the group experiments quite a bit with oddball time signatures borrowed from the Meshuggah handbook (see "Inhuman Affliction"), while showing no qualms about pilfering the progressive post-metal universe (Isis, Rwake, etc.) for luminescent streaks of harmonic sheet metal added to album standouts like "Samael the Destroyer," "With Legions," "Plague Campaign," and the sublime title track. At all times, Oceano match this dazzling dynamic variety with wildly polarized tempos ranging from the fastest blastbeat to the doomiest dragbeat, producing tunes as unpredictable as molten corrugated steel (e.g., "A Mandatory Sacrifice," "Disgust Your Kind," "District of Misery"). In the end, all this complexity and extremity pose quite a challenge for even experienced heavy metal fans, but for those capable of withstanding the nearly unbearable water pressure and impenetrably murky darkness, Oceano's mysteriously brutish grace will prove impossible to resist.