Every morning, when Matthew Barney showed up on the set of “River of Fundament” to begin that day’s shooting, he looked around at whatever bizarre army of cast, crew, and literati he had assembled, and said “I know this sounds crazy, but hear me out…”

At least, that’s how I imagine it. This three-part experimental opus from the artist who brought us “The Cremaster Cycle” fifteen years ago runs over five hours in total, and is one of the most insane, visionary, hubristic, obscene, sacramental, and memorable films you’ll ever come across. Writing about this movie is like dancing about architecture, as they say. But here goes anyhow:

“River of Fundament” is, at its heart, a tribute to Norman Mailer, the American novelist to whom all the adjectives in the paragraphs above could also apply, and who played Harry Houdini for Barney in “Cremaster 2.” A good portion of the first section of “River of Fundament” takes place in a replica of Mailer’s Brooklyn brownstone apartment, where a cross-section of New York’s literary and cultural elite has gathered to pay homage.

The slag flows in “River of Fundament.”

“Look, it’s Fran Lebowitz!” “Hey, isn’t that Jonas Mekas?” “Wow, Elaine Stritch! This must have been filmed a few years ago.” Those are just some of the thoughts you may have, depending on how pretentious you are. Other names that ended up my notepad: filmmaker James Toback, author Jeffrey Eugenides, former heavyweight champion Larry Holmes, and, of course, Dick Cavett. Deborah Harry is there. Salman Rushdie is there. Anyone who’s anyone was there, surely including many others gone unrecognized by your philistine correspondent. Some sort of bingo card might be warranted at future screenings.

Meanwhile, in a bathroom off the dining hall, a figure emerges from the titular sewage flow beneath the apartment to eventually take its place at the wake. (Barney has an affection for fancy words that refer to taboo bodily functions: the cremaster is the muscle that raises and lowers the testicles in a human male, and fundament is just a three-dollar synonym for poop.) There’s some gold-wrapped feces involved, which may be the closest Barney comes to self-referential satire.

Also meanwhile, weird stuff is going on at a Chrysler dealership in California, where a 1967 Chrysler Imperial is escorted ceremoniously by a mariachi band and a drum & bugle corps and then methodically, violently deconstructed, eventually emerging as a beautiful, golden 1979 Pontiac Firebird Trans Am. As Mailer undergoes multiple reincarnations during his wake, so does this automobile find itself transmogrified into successive forms.

Get it?

I think everything I’ve described takes place within the first hour or so of “River of Fundament,” which means I’ve only hinted at about 20% of what’s going on. For instance, Paul Giamatti is at the wake, but not as himself. No, he’s some sort of pharaonic conduit of mystical energy. (Have I mentioned that the film takes some of its characters, structure, and obsessions from Mailer’s generally reviled 1983 novel “Ancient Evenings,” set in a version of 12th-century BCE Egypt? Well, it does.)

Maggie Gyllenhaal shows up later on, as does Ellen Burstyn, both playing different iterations of Hathfertiti, the fictional Mailer’s wife and, in a sense, mother. Barney and his collaborator, composer Jonathan Bepler, originally envisioned “River of Fundament” as an opera, and there’s a huge musical component, from Native American chanting to florid arias by dueling dieties to an oboe-playing porn star.

That tidbit serves as good spot to mention that this film is not for the easily offended, or the easily grossed out. There are bodily fluids, or facsimiles thereof, in abundance. There is frontal nudity of all varieties. And, most startlingly, several shots are downright proctological, include one that involves a glass eye (spoiler alert!). This is one case where the “Mature Audiences Only” warning should be taken seriously. You’ve been warned.

The water flows in “River of Fundament.”

So, is “River of Fundament” just a piece of nihilistic, narcissistic, shock-jock art? Well, yes, except that’s not only what it is. It’s also dozens of other thing, including a depiction of the creative impulse on truly epic scales. There’s an industrial-level metal casting at a Detroit foundry that requires a crew of hundreds of workers. There’s a life-size replica of Mailer’s brownstone floating down a river. Either Matthew Barney is independently wealthy or he’s the greatest grand writer in the history of art (or at least since Michelangelo).

The Northwest Film Center is showing the three parts of “River of Fundament” in separate screenings over the weekend of June 3-5. As intimidating as it might sound, the only way to truly immerse yourself in its profane, sacred, ephemeral, visceral seas is to see the whole damn thing in one day. I’d say there should be a prize for anyone who accomplishes it, but there is one: the sense you’ve had a cinematic experience that can never be repeated.

(Part 1: 115 min., Part 2: 108 min., Part 3: 96 min.) Friday, June 3: Part 1, 6:30 pm; Part 2, 8:45 pm. Saturday, June 4: Part 1, 4:15 pm; Part 2, 6:30 pm; Part 3, 8:45 pm. Sunday, June 5: Part 2, 4:45 pm; Part 3, 7 pm. All screenings at the Northwest Film Center.) GRADE: BEYOND GOOD AND EVIL