Most filmmakers who want to unsettle you in a horror movie will reach for a familiar set of tools: slashers, demons, shock cuts, soundtracks that go boom! in the night. But in “Crimes of the Future,” the writer-director David Cronenberg is out to provoke and disturb us with something far more traumatic than mere monsters.

Am I talking about the fact that in the distant future where the film is set, human beings grow mysterious new organs in their bodies? Or that having those organs removed through surgery has become, for a creepy rebel aesthete named Saul Tenser (Viggo Mortensen), a species of performance art? Or that people no longer experience physical pain, and will therefore stand in the street late at night cutting each other for cheap thrills, as if they were shooting heroin in a back alley? Or that surgery itself, as someone puts it, has become “the new sex”?

If you see “Crimes of the Future,” you’ll witness all of these outrages, and a few more besides. Yet the most forbidding aspect of the movie isn’t any of those squeamish occurrences. It’s the fact that “Crimes of the Future” makes you feel like you’re being attacked by metaphors. It’s a body-horror movie that keeps growing new “ideas.” Like most of Cronenberg’s films, it works from the head down.

Cronenberg has always been a metaphor junkie. His first film to play theatrically, “They Came From Within” (1975), was set in a Toronto housing complex where slithery parasites turn the residents into rampaging sexual beasts — zombies of the libido. In “The Brood” (1979), the first film of his to win the critical acclaim that would attach itself to Cronenberg for the next 40 years, a woman in the middle of a custody battle parthenogenetically births a brood of dwarf children who are presented as the incarnations of her “rage.” By the time he got to “Videodrome” (1983), his first major studio production, Cronenberg began to go hog-wild with metaphor, making a cracked hallucinatory thriller about sex, violence, and technology that climaxes with someone’s stomach turning into a VCR. The last words spoken by the hero are “Long live the new flesh.”

Cronenberg has long been fixated on the old flesh vs. the new flesh. What’s the new flesh? It’s flesh that changes, mutates, comes from within. It’s cancer. It’s the eruption of forbidden emotion. It’s also representative of something about us that’s “evolving.” Cronenberg more or less patented the genre of body horror, which means that for him the body is never just the body. It incarnates the people — and the monsters — we are inside. It’s bad dreams made flesh.

Some of “Crimes of the Future” is gory and disturbing to behold, if not quite on the “Warning! May be too much for the faint-hearted!” level that the film’s William Castle-worthy advance publicity has suggested. That said, the movie, like so many Cronenberg films, is a gut-twister that is really, just underneath, a painstakingly chewed-over and cerebral experience. It’s an outré nightmare that keeps telling you what to think about what it means.

Cronenberg became an incredibly eclectic filmmaker (his work includes adaptations of “M. Butterfly” and “Naked Lunch,” the graphic-novel thriller “A History of Violence,” the psychotic maze film “Spider” and the Freud-and-Jung costume drama “A Dangerous Method”), but “Crimes of the Future” marks a return to the formative squishiness of his early movies. It has links, as well, to the conceptual pain-freak “transgression” of “Crash.” That film remains the most infamous of Cronenberg’s career, though not because it’s so taboo. It’s more that anyone of common sense would watch it and think, “Really? Car crashes as an erotic turn-on? Is that a joke?”

“Crash” was Cronenberg pushing his metaphor madness to the wall, and he does the same thing in “Crimes of the Future.” But this is a much more compelling movie, because in its gloom-future way it invites you into the blood-soaked dystopia it creates. The film lures you in and tugs you along, abetted by Howard Shore’s fantastic score, which at times suggests the slow movement of Beethoven’s 7th Symphony as rewritten by Boris Karloff.

The film opens with a boy taking bites out of a plastic wastebasket, and his mother then smothering him with a pillow — presumably because she can’t stand having a child who munches on wastebaskets. (As it turns out, that’s exactly the reason.) We then cut to Saul Tenser, the performance artist from surgical hell, waking up in an organic seed pod that looks like it was purchased at a furniture store called Crate and Alien. It is, in fact, an OrchidBed, designed to anticipate and conform to the body’s every need. Saul sleeps in one because that’s how brilliant and damaged and sensitive he is. (He also has an even stranger chair for eating, which makes him look like a stroke victim.) Mortensen imbues the character with a wounded mystique of cringing rock-star transcendence. Walking around in his hooded shawl, he’s like Death from “The Seventh Seal” crossed with Kirk Douglas, though he talks in a gravel purr that may put you in mind of several Batmans.

“Crimes of the Future” was shot in Greece, and the settings have a crumbly European flavor that feels like Venice at 3:00 a.m. Yet this is very much a world beyond ours. Thanks to “Accelerated Evolution Syndrome,” the human race is mutating (that’s why pain is disappearing), and “desktop surgery” has become a thing. Saul does his performance art in collaboration with his live-in partner, Caprice (an insinuating Léa Seydoux); they plan out each show as a kind of medical-theatrical catharsis. As the audience stands there in awe, staring while the music throbs, Saul lays on the operating table and Caprice, using a jellied controlled panel, wields pincers that look like skeletal arms to slice him open and pull his abdomen apart, reaching inside for the new organ he has harvested. Is this a sick spectacle? It sure is. But only in a Cronenberg film would it be presented as a form of entertainment.

There’s a plot. It has something to do with the National Organ Registry, a very William S. Burroughs-sounding organization that tracks new organ growths — it’s run by Wippet (Don McKellar), a goofy bureaucrat, and Timlin (Kristen Stewart), his breathy and timid assistant, who gets so turned on watching Saul’s latest surgery performance that she flips for him, as if he were the Jim Morrison of public tumor removal. Stewart, at moments, seems to be doing an “SNL” parody of Kristen Stewart at her most breathy-nervous, but she does it knowingly; her scenes have a charge.

There’s another organization, this one having nothing to do with the sinister government. It’s a cult of people who’ve undergone their own evolution, which results in their producing and eating what appear to be purple candy bars. Yes, another metaphor! But have no fear, it will all be explained. There is also a nightclub scene with a dancer who has his eyes and lips sewn shut and ears all over his body. In “Crimes of the Future,” you get the feeling that Cronenberg wants to be William Castle, William S. Burroughs, and H.R. Giger all at the same time.

That 8-year-old boy who got killed in the opening scene comes back into the movie. His father, Lang (Scott Speedman), wants to give the corpse to Saul and Caprice so that they can do an autopsy on it during one of their performances. Once you get onto the movie’s wavelength, even a twist like this doesn’t throw you. It’s like, “Nightclub dissection of the kid who ate wastebaskets? Why not?” I won’t give away what happens, except to say that the kid’s father is one of those purple-candy-bar munchers, and that has everything to do with the way the underground cult — and maybe the human race — is evolving. The theme of “Crimes of the Future,” sealed by its final scene, might be: You are what you eat. What’s provocative about Cronenberg’s grand metaphor, but also a bit corny about it, is that it has to do with technology and how it’s changing us, but the director’s point of view, as it has been for decades, is that of someone looking askance at technology because he finds it to be alien. Yet what if it’s not? “Crimes of the Future” will prove too extreme for most viewers, but one reason the film is so extreme is that it’s mired in fears most of them have long looked past.