When the end credits started rolling on Alex Garland’s brain-twisting “Annihilation,” the first thought that popped into my head was: If Stanley Kubrick tried to make “2001: A Space Odyssey” today, would a risk-averse, marketing-dependent studio have backed him?

It’s not an idle question, because Garland’s science-fiction horror thriller has much of the same visual flourishes, intellectual weight and soaring ambitions as Kubrick’s landmark space epic — even if it doesn’t quite match Kubrick’s skill at imparting grand ideas.

Paramount Pictures, which is releasing “Annihilation” this weekend in the United States and Canada, and eventually in China, sold the international rights to Netflix, a sure indication that the studio had no confidence in the movie’s box-office prospects.

Certainly if one has shares in Paramount’s parent company, Viacom, the difficult-to-market “Annihilation” might induce some heartburn. But if one goes to the movies to have one’s mind blown open by the new and the challenging, this is something to see.

Natalie Portman stars as Lena, a biologist completely committed to her work studying the genetic makeup of cells. We learn very soon why she buries herself in her work: She’s filling the hole left since her soldier husband, Kane (Oscar Isaac), went missing on a special-ops mission and was presumed dead a year earlier.

One weekend, out of nowhere, Kane appears in their home, and Lena is overjoyed at his return. But something seems off, as Kane gives no information about where he was, what happened to his unit or how he made it home. He then starts coughing up blood, and Lena calls an ambulance — but the trip to the hospital is intercepted by mysterious figures in black SUVs.

Lena wakes up in a top-secret lab, being questioned by a government psychologist, Dr. Ventress (Jennifer Jason Leigh). Eventually, Ventress informs Lena that the lab is near a mysterious force, called The Shimmer, that started at a coastal lighthouse and has been slowly spreading across southeastern swamp land. Military units have been sent inside to investigate, but only one person has ever come out: Kane.

Ventress forms a unit of scientists, all women (played by Gina Rodriguez, Tessa Thompson and Tuva Novotny), to enter The Shimmer. Lena volunteers to join them, but only she and Ventress know of her connection to Kane.

We know from the beginning that something bad happens — Garland’s script (adapting Jeff VanderMeer’s novel) frames the story through an after-the-fact interrogation of Lena. What we don’t know is how bad, or why, and that’s where Garland’s tensely thought-provoking script reveals its most haunting surprises.

Portman conveys both scientific curiosity and desperate urgency as Lena seeks the answers to The Shimmer and her husband’s horrific experience there. She’s well matched by the ensemble, particularly the tough-talking Rodriguez and the sensitive Thompson.

Garland showed a deft hand blending visual-effects prowess and menacing intelligence in the robot drama “Ex Machina,” and he repeats that trick brilliantly here. The deeper Lena and Ventress’ team gets into the area of the spreading Shimmer, the more fascinating and dangerous the terrifying wonders they encounter — all the way to a shattering finish that is as undefinable as it is unforgettable.

★★★1/2

Annihilation

A team of scientists faces the unknown, and their own fears, in this mind-expanding horror thriller.

Where • Theaters everywhere.

When • Opens Friday, Feb. 23.

Rating • R for violence, bloody images, language and some sexuality.

Running time • 115 minutes.