Idris Elba and Matthew McConaughey in "The Dark Tower." (Ilze Kitshoff/Sony Pictures Entertainment/Sony Pictures Entertainment)

A movie doesn’t have to be rated R to be scary, but it should have a villain who doesn’t remind you of the test-tube love child of Voldemort and a second-rate stand-up comic moonlighting as the host of a local dance club’s Goth & Industrial Night. As the glibly wisecracking, well-coiffed demonic sorcerer Walter Padick — also known as the Man in Black, thanks to his self-explanatory, funereal attire — Matthew McConaughey in the PG-13 Stephen King adaptation “The Dark Tower” is unlikely to evoke deathly shivers so much as a terminal case of the giggles.

“I hope you don’t mind me making myself at home,” Walter says to a couple whose kitchen stove he has just commandeered, after materializing from the alternate dimension in which he lives. “Where I come from, we don’t have chicken.” Bada-bing. Later, when he resumes his campaign of universal annihilation — because, as previously noted: Bad Guy — Walter quips, brightly, “Have a great apocalypse.”

There is nothing great — or even particularly apocalyptic — about “The Dark Tower.” Inspired, in only the most generous sense of the word, by King’s violent, eight-volume, supernatural-western fantasy series, the film by Nikolaj Arcel (“A Royal Affair”) is a watered-down, kids’-movie version of King-ly horror. Walter’s brooding nemesis, the equally fashion-forward Roland Deschain, a.k.a. the Gunslinger (Idris Elba), isn’t even the movie’s true hero, although he has been stalking Walter, pistols blazing, since time immemorial. (Roland’s guns are said to have been forged from the steel of King Arthur’s sword, Excalibur, but that doesn’t make their bullets lethal to Walter, who catches them in his hand, like flyballs.)

In a sop to its apparent target audience, the main protagonist of “The Dark Tower” is a troubled tween named Jake Chambers (Tom Taylor), who seems to have accidentally wandered into this movie from the set of a young-adult drama about alienation.


Jake Chambers’s Tom Taylor is the real protagonist of “The Dark Tower.” (Ilze Kitshoff/Sony Pictures Entertainment)

As the movie opens, Jake has been having vivid nightmares in which he sees Roland do battle with Walter. As illustrated in the film’s dreamlike prologue, Walter has been kidnapping children and hooking them up to a high-tech contraption that harnesses their psychic energy to create a laserlike beam that he uses to chip away at the titular Dark Tower, a mysterious, linchpin-like skyscraper that somehow holds together the film’s various multiverses. Jake lives in modern-day New York — or, rather, in the movie’s rendering, on Keystone Earth — while Roland and Walter inhabit a wasteland known as Mid-World, which seems to contain both medieval villages and Walter’s high-tech lair, staffed by laughably sycophantic, bumbling minions out of a live-action version of “Despicable Me.”

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Let’s make this easy: “The Dark Tower” isn’t frightening, or even, despite some serviceable action and special effects, very interesting, except perhaps for viewers too young to know better, or for Stephen King fans especially susceptible to outright pandering. Adapted for the screen by Arcel, with the assistance of Akiva Goldsman, Jeff Pinkner and Anders Thomas Jensen, “The Dark Tower” seems to have been driven less by a coherent screenplay than by a desire to stir together miscellaneous scraps from the universe of King’s novels and films. References to Pennywise the clown from “It” and to the Overlook Hotel in “The Shining” are scattered throughout. Even Jake’s powerful clairvoyant ability — referred to as the “Touch” in King’s books — is here called the “Shine.” Other ingredients, in addition to the obvious “Harry Potter” influence, include “Star Wars” and every cowboy cliche known to man.

King’s “Dark Tower” series has been called his magnum opus, a great work that attempts, in its sprawling ambition and 4,000-plus pages, to tie together many details from his literary oeuvre. But the only part of that description that applies in this case is “work.”

In the buildup to the release of “The Dark Tower,” fans of the source material have expressed concern that the movie’s brisk running time would underserve the books’ grand themes. Trust me: When the house lights come up, no one is going to wish they could sit through a minute more of this chore.

The Dark Tower (93 minutes, at area theaters) is rated PG-13 for mature thematic material, sequences of gun violence and action.