“Go with what you know” seems to be the guiding principle of H&M’s designer collaborations. Last year, Donatella Versace put on a schmoozy runway show for her fashion and celebrity pals, even supplying live performances by the normally hermetic Prince and the less hermetic Nicki Minaj. Can’t you just hear the phone call? “Pdeence, dahlink, weel you sing-a for me?”

For its collab (pictures of which were released last week), Maison Martin Margiela pulled out all the stops, and then some, with a sprawling bash last night that was as much an art expo and warehouse rave as a launch party. An abandoned, derelict high-rise building in lower Manhattan, which appeared to be further gutted and distressed by MMM crew, served as the Halloween-ready, Hollywood-worthy setting. Inside, artists had filled eight floors with site-specific works incorporating pieces from the collaboration, or “re-edits” of the house’s greatest hits over the years. On display were Noémie Goudal’s photos featuring the collection blending in with nature, while Brooklyn-based Daniel Arsham embedded lifelike mannequins into a wall, their bodies mostly covered, as if wallpapered over. This is where Selma Blair and Mena Suvari hovered for most of the night, so that if you squinted, it was hard to know where a plastic mannequin ended and a real-life actress began. All floors had a central balcony that overlooked the lobby below, where choreographer Anne Teresa De Keersmaeker staged a performance in which dancers—again in pieces from the collection—writhed in sand and made shapes with their bare feet.

Finally, on the ninth floor, after some huffing and puffing, we reached the apex and climax of the evening. Shopping! Not just any shopping, mind you, but skilled ninja-level hoarding that, if you weren’t careful, could put you on the business end of a flying stiletto heel. Perilous though it was, we ventured into the fray, buffeted by large white shopping bags and tripping over items flung on the floor in haste. Nothing was sacred as models, who had been angelically smiling for the cameras just moments earlier, tore into racks of duvet coats and oversized blazers with terrifying zeal. People you thought you knew turned rabid, all too willing to trample children if it meant scoring the last pair of sequin leggings or tromp-l’oeil leather purse.

By night’s end, the DJ had what remained of the partiers kicking up their heels under a shower of silver confetti. Many of the songs he played harked back to the 80s—beginning with Nina Hagen’s New York, New York—around the time the label was founded and fetes of this magnitude and splendor were a nightly occurrence.