Number 43 Watson Crescent, in Edinburgh's Polwarth district, might not be here by the time you read this. The property was condemned some time ago, and the bulldozers are due any day. Last week, however, courtesy of Edinburgh conceptual artist Spotov, the ghosts left over from the building's former life as the Edinburgh home of the Royal Antediluvian Order of Buffaloes gathered in its crumbling club-house for one final fling.

Spotov's hourly performances of DMOB Club, or Dislodge of the Mid-diluvian Order of the Buffaloes, to give it its full title, have been the best-kept secret of the Fringe. The Buffaloes are an order with similarities to the Masons, founded by nineteenth-century theatre technicians. These days, while the organisation still exists worldwide, the once plush rooms that housed their meetings are out of time, deserted or, in Number 43's case, falling down.

When the letterbox of the building's battered red door flaps open, the naked bulb behind it looks less than inviting. I've booked an all-too-rare appointment for the performance, and been instructed to use a secret knock to get in.

The door opens, and a young girl introduces herself as Poppy, welcoming me into a tiny vestibule made even smaller by a desk on which rests some arcane metal contraption. I'm invited to sign a disclaimer and advised that, as long as I do what I'm asked, no harm will come to me. Then Poppy measures my head, asking me to lean, face down, into the machine.

Blindfolded, I'm led by strangers out of the room to some stairs, as Poppy's voice grows faint. When we stop, a man's voice tells me grandly to kneel, then to remove the blindfold. I find myself bowed down in the decrepit remains of a gents' lavatory, expanded by mirrors which concertina either side of me. Voices off ask me forcefully and at length if I agree with the terms laid down for me, possibly for reasons of insurance, legality and liability in case of my demise. I confirm in the positive, and await my fate.

Of the following 35 minutes, all I can reveal is that I am hooded, bound, restrained, tied up with blankets and buried alive. Rubble is underfoot and in my eyes. Then, my initiation apparently complete, I am wheeled at speed around a room where games are played in earnest by strange creatures sporting ginger beards and horns.

Most of these wondrous mysteries are witnessed through the fragrant blankets that cover me. Whenever my sights are cleared, the thing that lingers in my memory most is the constant presence of a solitary bull's visage, which looms large wherever I walk.

As a satire, pastiche or memorial, DMOB is at once full-on, terrifying and stimulating in its extremes. Claustrophobics and those scared of the dark need not apply. Yet given that Spotov and her collaborators have previously burrowed their way through rubble-strewn tunnels on the former site of Edinburgh's Bongo Club, and worked in similar found spaces in other parts of Scotland, Berlin and beyond, this should come as no surprise.

And DMOB's antecedents are many. A Polish company brought to Edinburgh in the late 1980s by Richard Demarco buried audiences of one in cages below ground, with the performance taking place above them. The authorities were timid to such self-expression, alas, and somewhat inevitably shut it down. Later, Angus Farquhar's NVA Organisation led tours around the dilapidated top floor of Glasgow's Central Hotel, where the stylised emotional detritus of the rooms' occupants was modelled into an after-hours installation.

DMOB, I'm exhilarated to say, goes further. At the end of my journey, I find myself back in the vestibule with Poppy. Given that this alcove is as far as any woman is allowed into the order's vestiges, she is keen to hear my tale. I recount it as best I can, and am ushered on to the street. As I walk back into the city, I realign my senses and attempt to take stock of what has just occurred. Was it a dream? Once the building is demolished, after all, there will be no archive or record, save these scraps of hastily written prose. If number 43 is still standing, you might get to go. E-mail leave