Over its seven-year gestation, Christmas on Mars had come to represent everything wonderful and frustrating about the Flaming Lips. As much as we loved the idea of Wayne Coyne producing a sci-fi flick in his backyard with hardware-store materials, the Lips' musical production became less frequent-- and less consistent-- during its making. 2006's scattershot At War With the Mystics tried to cut down on the lightness of their two previous landmark albums but was largely overwhelmed by cloying singles ("The Yeah Yeah Yeah Song", "Free Radicals") that felt like little more than excuses to shoot off their confetti cannons. The trio's desire to produce crowd-pleasing spectacle-- whether on stage or on film-- had seemingly taken priority over their desire to be a band.

But when Christmas on Mars finally surfaced in late 2008, it came with a peace offering to fans longing for a return to the band's bizarro roots: a full-length soundtrack of unsettling instrumentals that conjured the film's icy desolation. Now, rather than close a chapter on this seven-year saga, the Flaming Lips have taken a dramatic left turn with their Mystics follow-up-- the double album Embryonic is the band's most audacious undertaking since 1997's Zaireeka. The sprawling 70-minute marathon ruminates on themes of madness, isolation, and hallucinogenic horror, translating them into an unrelentingly paranoid, static-soaked acid-rock epic. Embryonic actually feels like it was produced in one of Christmas on Mars' hermetic space-station labs, with squelching equipment that takes a few moments to warm up and frequent instructional studio chatter that gives the impression of a subject under observation.

There's a raw directness to Embryonic that's been largely absent from Lips records since the mid-90s. For the first time in years, they've made an album that actually sounds like a band playing live together in a small room. In light of Mystics' overly processed, grab-bag quality, the holistic, audio-vérité approach on display here is remarkable-- the record is extremely dense, initially overwhelming, but unusually rewarding upon repeat listens. Like the double-disc, high-concept rock epics of yore (think Physical Graffiti or Bitches Brew), it captures them at their most sprawling and ambitious, boldly pushing themselves towards more adventurous horizons.

Musically, too, Embryonic leans heavily on the Lips' formative 60s/70s psych-rock influence (like In a Priest Driven Ambulance's "Take Meta Mars" before it, Embryonic's formidable opener "Convinced of the Hex" grooves heavily on Can's "Mushroom"), but never before has the band recorded an album so unwaveringly sinister, or so devoid of pop-song levity. (Hell, even Zaireeka had "The Big Ol' Bug Is the New Baby Now".) Wayne Coyne no longer assumes the role of the endearingly creaky, puppet-toting crooner. Instead, he's a world-weary fatalist describing scenes of environmental holocaust in a chillingly unaffected monotone on the rampaging "See the Leaves". Or he's a cult leader deviously summoning his minions on "Sagittarius Silver Announcement", before leading them to a fiery demise on the monstrous, stoner-metal onslaught of "Worm Mountain" (featuring fuzzbox-stomping assistance from MGMT). The atmosphere of dread reaches its fever pitch in the album's spellbinding seven-minute centerpiece "Powerless", where, over top a coolly ominous bass riff, Coyne's nervous verses yield to a Syd Barrett-on-Mandrax guitar freak out.

There are brief respites amid Embryonic's thundering eruptions, but even these carry a calm-before-the-storm unease: On paper, "I Can Be a Frog" reads like another of Coyne's animal-populated nursery rhymes, but the foreboding orchestration and giggly background squawks (courtesy of Karen O) render it too creepy for kindergarten. And the vocoderized lullaby "The Impulse" serves only to make the screaming intro to strobe-lit freakout "Silver Trembling Hands" all the more startling. True to an album named Embryonic, there are tracks that aren't fully formed (namely, the drunken Bonham stumble of "Your Bats" or the free-psych splatter of "Scorpio Swords"), but even in its slighter moments, Embryonic exhibits a renewed sense of fearless freakery for a band who so recently threatened to lapse into stagy routine.

"I wish I could go back, go back in time," Coyne sings on "Evil", Embryonic's most conventionally Lips-ian ballad, but the nostalgic impulse is immediately undercut by the admission that "no one really ever can." Perhaps Coyne is anticipating the confused reactions of recent Lips converts expecting more life-affirming anthems along the lines of "Do You Realize??" or "Race for the Prize". But given the band's history, Embryonic's sea change arrives right on time to herald a new Flaming Lips for a new decade. Back in 1990, In a Priest Driven Ambulance signaled the Lips' transformation from garage-punk misfits into a splendorous, kaleidoscopic rock outfit; 1999's The Soft Bulletin reconfigured them once again into a sophisticated, sincere symphonic-pop troupe bestowed with increasing commercial acclaim and street-naming ceremonies in their honor. We can only hope that, as we enter the 2010s, Embryonic portends yet another new phase for the Flaming Lips-- one that's equally as improbable and rewarding as the ones that have preceded it.