I do up my fly, look around and squint from the glare of fluorescent lighting. The whole of this deserted gents toilet is vibrating and constituent parts buzz or rattle in sympathy with each bass thrum: poster frames, soap dispensers, mirrors, taps. There is music coming out of the fucking hand dryer. Yes, it's just a whistle-stop slash with only a few inches of wall separating me from the stage; but for a moment I'm on board the departing mothership set for vast infinity. Well, it's been the sort of night that encourages an over-active imagination.

If we lived in a righteous land, when kids get together to form bands they would generally sound a lot like GNOD do tonight. Their releases to date are stuffed with ambient/avant-noise gems but here we get the heavier, dronier end of the deal. And it kills. For the first ten minutes bedlam pounds around a single, unholy bent bass note. Primitive, tribal, sexy, monolithic, recollective yet starkly futurist. Like a Hawkwind show in emergency lighting, six barely-distinguishable figures propel a jet of sonic overload into a blurring room. There are acid squelches, proto-punk screeds and a frontman in the Malcolm Mooney/ Iggy Pop/ Pete Voss(!) mould whose wired proclamations wander in and out of the turbulent mix. Why do so few bands try and sound this amazing? All this mystical purpose and harnessed commotion make GNOD the type of collective you want to join in their underground compound, never mind listen to.

There's a real mix of ages and types in here tonight; just dotted around us are a young couple indulging in some stoned 'Tales of the Unexpected'-style dance moves, a huge dude in an Eyehategod t-shirt, neatly-coiffured gents, Tommy Saxondales, charming student girls and an elderly fellow with a carrier bag. Acid Mothers Temple & The Melting Paraiso UFO seem to bring together significant numbers of disparate people who share a love of extreme freak-outs. Surely that's a marvellous thing?

A burst of improvised space-jazz and 'Chinese Flying Saucer' kick-starts with its B-movie Jimmy Page riff. Kawabata Makoto handles his Strat like a mischievous turkey, stroking it, admonishing it, strangling it. He raises the headstock up towards the roof as if it threatens to fly away, before pulling it back into his grasp amid all manner of screams and squawks. Higashi, centre stage, is more impassive, the sage wizard manipulating frequencies and oscillations, weaving his magic. The set visits a cappella folk, noise jams, throat singing, rock 'n' roll, blissfully trippy drone and the aforementioned piss break. While other bands would look ridiculous shifting between styles so wantonly, for these fellas it seems perfectly natural. A watertight rhythm section allows even the most wild freeform excursions to return to a driving pulse.

Exposure to all this at high volume makes one giddy; slightly hysterical. It's great fun, it rocks hard but there are moments when I can close my eyes and allow my mind to wander; to the view of a crystal-clear sky at 30,000 feet, to the evolution of cats. Then, SLAP. A deafening crescendo, the smell of naphtha and Kawabata's guitar is aflame. An early Christmas for that turkey. Astonishing stuff.

Photo courtesy of the wonderful Cathy Soreny