Justin Lowe and Jonah Freeman

Wednesday night, beneath an inverted five-pointed star hanging from the ceiling of the Masonic Lodge at the Hollywood Forever Cemetery in Los Angeles, the artists Jonah Freeman and Justin Lowe presented “Shadow Pool: A Natural History of the San San International” to a crowd of 350 that included Gus Van Sant and Jeffrey Deitch, who commissioned the piece for the Museum of Contemporary Art. This multimedia extravaganza — part slide show and lecture, part fashion show, part art installation, part rock ‘n’ roll freakout — is the latest iteration of the fictional parallel universe the duo has been imagining and manifesting since 2008, with installations at Ballroom Marfa, Deitch Projects, Miami Art Basel and Country Club at R.M. Schindler’s Buck House in West Hollywood, which they transformed into an artfully ravaged psychedelic laboratory, the onetime site of out-there experiments with a drug called “Marasa.” “Shadow Pool” expands upon and then explodes this mythology, holding up the shards for our sensory pleasure, and confusion.

Described by Lowe as “a spectacle that eclipses a spectacle that eclipses a spectacle,” the piece unfurls the narrative of the San San International, the largest convention in the world, held at a monolithic convention center located between San Francisco and San Diego (hence the name San San). Like a wild-haired professor seated on a throne onstage at the Masonic Lodge, Freeman explained in a deadpan voice that the center had 13 floors, thousands of entrances, “a lot of atriums,” and that Lionel Richie and U2 had performed there. So massive is the San San “Metroplex” that it has given rise to wildly stylish street gangs with names like the Shade, Starchamber and the Fort, “techno hippies represented here by Robert Redford,” added Freeman, commenting on a slide. As footage from old Doublemint gum commercials played on the screen, Jennifer Herrema and her new band Black Bananas settled into a heavy psych-synth groove, giving a menacing air to the grinning, green-clad twins.

The music got louder, smoke filled the air, and models representing the various tribes began walking through the hall bearing artifacts and relics. A woman in a lenticular dress carried a silver pig’s head on a platter, presumably an homage to the yippie prank, and another in a glittering black evening dress bore Rodarte shoes aloft. And they kept coming: Starchamber, vaguely Tibetan in robes and furs, offering crystals; the Hindu Preppies, who wore garlands of marigolds and mehndi tattoos with their country club attire; “’80s curators” in jewel tones; savagely tan blondes in salt-encrusted prom dresses; a quartet in Lady Di wigs; and a group in airbrushed pornographic T-shirts, carrying neon-colored frosted cakes. Some of the most hilarious and imaginative pieces were caftans and hoods made from printed towels found on the Venice boardwalk and collaged together — elephants grafted with sharks, panther bodies with human heads.

It turns out somebody else was a fan: “Jeffrey Deitch is going to wear one of them when he does his speech at the MOCA gala [on Saturday night]!” said Jhordan Dahl, who styled the fashion portion of the show with Katie Casey. The two women, whose last collaboration was designing costumes for Jennifer Lopez’s dancers, spent the past four months sewing, combing thrift stores, borrowing from stylist friends and pulling from their own closets to create more than 100 pieces. They also cast the show, enlisting pals like the actor Henry Hopper; the artists Brian Butler, Maximilla Lukacs and Alia Penner; and fellow designers like Brian Kim and Michalyn Andrews. A mother and her two young sons were recruited at the Raymond Pettibon opening at Regen Projects, and it didn’t stop there: Dahl’s grandmother was in town, and, the designers recall, “We were like, ‘Wait a minute, put on this fake Versace dress!’ It was like that scene in ‘Clueless’!”

Relaxing with a glass of Champagne before heading to the Mandrake in Culver City, Lowe joked that the overall effect was “like you’ve been living in Topanga Canyon for three years and you just showed up at J.F.K. — or Newark! For better or for worse.”

Unfortunately Dahl’s grandmother wasn’t available to comment; she’d already left for the after-party.