The Mothership has returned. There are stormtroopers - four chunky male dancers in baseball pads and scuba masks - on manoeuvres. There are back-up troops - two singers, a guitarist, a bassist and the imposing Cutmaster Swiff behind the decks. And at the centre of the madness, two emissaries from the land of Stankonia.
One is wearing a floor-length trenchcoat, tight blond wig and evil grin, and looks like the problem offspring of Rick James and L'il Kim. This is Dre. The other is heavier, dressed-down and looks misleadingly like a typical rapper. This is Big Boi.
Alternatively known, of course, as Outkast, or "The one and only Outkast," as Dre would have it.
Right now, the Atlanta duo find themselves in an unusual and powerful position, as hip-hop inheritors to the freak-funk of the '70s, to both George Clinton's dayglo P-funk party music and Sly Stone's serpentine, insidious, politically-indignant grooves. When they sing 'Rosa Parks', dodging the dancers and provoking a pointed singalong of, "Everybody move to the back of the bus," it's plain Outkast, combining social history and good-time showbusiness with rare acuity.
It's the latter, however, that most people notice. Dre and Big Boi are conscientious enough to critique ghetto economics (on 'Red Velvet') or the repercussions of the Gulf War (in 'BOB'). But tonight, they're playing a faintly gruesome corporate shindig thrown by a credibility-chasing jeans manufacturer, just the kind of multinational presence you'd hope would be barred from Stankonia.
Maybe someone forgot to tell Outkast - after all, they only plug their own clothing line during the show, leaving one of their backing singers to big up the sponsors at the death. Instead, there's a slick professionalism to the outlandishness, a drilled spirit that makes the show - corporate bullshit notwithstanding - one of the best London's seen this year.
Highlights? A frenetic tumble through the Latino-twisted 'Humble Mumble'. 'So Fresh, So Clean' scuffed up with a barrage of scratching from Cutmaster Swiff, and featuring Dre and Big Boi being dusted by their dancers. And the final, extraordinary 'BOB': beats accelerating to hyperspeed, dancers falling into a fierce martial stomp, guitars howling, supremely organised chaos.
Few bands can be so raging and so euphoric simultaneously, and still be plausible. But how long can Outkast continue to be so conscientious since they've become international superstars? For now, it's enough to exploit the contradictions and keep partying, at least until 'Stankonia''s sequel is made.