Das Racist's "Combination Pizza Hut and Taco Bell," an unlikely but undeniable out-of-nowhere breakthrough hit/joke/meme, turned heads across the Internet and beyond in 2009.

The following year a pair of improbably solid, skilled, but still impishly playful free-download mixtapes established their no-joke chops, and now the smarty-pants Brooklyn rappers deliver their first legit, purchasable album with goodwill (and talent, and charisma) to burn.

And they have little to prove except their ability to keep a very good, emphatically original thing going.

Relax is an odd handle for such a manically wired, hyper affair, as the disc blends dense, reference-strewn, culture-jamming rhymes; absurdist non sequiturs ("I'm DJ Khaled/I'm a daikon radish"); cannily irreverent racial critiques; eggheaded egg-tossing ("Rapgenius.com is white devil sophistry"); fake patois; and gleeful gibberish.

If there's a discernible new development here, it may be an increased sense of toughness, both musically and lyrically.

At least intermittently, Relax seems geared toward beefing up Das Racist's hip-hop bona fides -- i.e., basically, their sincerity -- no mean feat for such unrepentant trickster-hipster satirists.

So listeners get rampant (largely unconvincing) drug hustling references, the self-explanatory (evidently un-ironic) "club banger" "Booty in the Air," and, on the pace-setting title track, a rare moment of personal introspection -- Heems rapping about his immigrant parents in 1980s Queens ("from holding me to bagging groceries at the Pathmark") -- juxtaposed with the uncharacteristically straight-faced boast "these days I mostly focus on my bank account/I ain't backing out til I own a bank to brag about." Indie rap-wise, it doesn't get much tougher or more soberly serious than El-P, who both produces and guests on "Shut Up, Man" with characteristic chilly digi-funk steeliness, Das Racist following suit impeccably (but with poop jokes).

On the other hand, there's the bubbly synth pop of "Girl," a clear, tongue-in-cheek, pop-rap piss-take; the lite electro-bhangra fusion "Punjabi Song"; and the frothy, fun-loving "The Trick" (produced by Vampire Weekend's Rostam Batmanglij, with a heavy nod to Tom Tom Club).

Their range is impressive, but nobody's gonna mistake these guys for remotely conventional rappers -- nor, presumably, would they want that.

One quibble: while "Combination Pizza Hut" is referenced twice, there's nothing here approaching the catchiness of that song's indelible hook.

Granted, they're not fishing for another viral earworm here, but you'd think they could come up with something better -- for the lead single, no less -- than "Michael Jackson"'s feeble placeholder of a refrain.