A pre-fabricated urban legend comes to the big screen in “Slender Man,” essentially a random mash-up of horror film tropes and effects that doesn’t amount to much that’s frightening.

Director Sylvain White, of “Stomp the Yard” and a lot of episodic TV in the many years since, hurls fish-eye lenses, hand-held shaky cameras, tracking zooms (in homage to Spike Lee), all sorts of in-camera effects to simulate how crazy teenage girls go after they’ve summoned Slender Man.

The monster, an Internet creation of the child-snatching variety, is a faceless version of Lurch, the butler for The Addams Family — wraith-thin, faceless, inexplicably wearing a white shirt and tie.

He’s the ghost of a Reservoir Dog or one of the Men in Black? In any event, he’s better in fleeting glimpses than in close-up.

The movie mimics what’s allegedly been dominating teen and tween slumber parties the past decade, girls hearing or reading about the legend, finding online help in “summoning” the demon, and (in the movie at least) suffering the consequences.

“Guys, we SO have to do this.”

Four BFFs (Joey King, Julia Goldani Telles, Jaz Sinclair, Annalise Basso) , essentially egged on by a quartet of boys who say this is what they’re trying this weekend, watch the online video (Shades of “The Ring”), hear the bells toll and start having nightmares.

“What did you see?”

What did YOU see?”

The thing is, you SEE the Slender Man — often glimpsed in the background, in foggy woods, glimpsed in “Bigfoot” style online videos — and he’s got you.

“Some are haunted, some go mad and some he takes.”

A week later, one of their number disappears on a school trip.

You can guess the order the girls will have their Slender moment of truth by the stereotypical casting here  — brunette, brownette, African American and redhead.

The kids frantically do online “homework” to figure out how to retrieve the missing friend, and that just gets them in deeper. Warn a boyfriend or younger sister “Do NOT watch the video,” and they do what teenagers do.

It’s not laughably off, and give White credit for the picture’s fairly eerie tone and look — darkened streets, foggy forests of spindly pines, shadows and more shadows. It’s just not worth more than the occasional hair-raising instant.

But here’s something that “Slender Man” gets right — casting Joey King of “The Conjuring,” Netflix’s “The Kissing Booth” and “White House Down” as Wren, the punk/Goth girl in the quartet. King sells the pants-wetting terror of facing supernatural doom better than anybody else in this movie, or most of the horror movies since A Quiet Place.”

If everybody else had faked being scared as perfectly as Ms. King, maybe we’d be scared, too.

MPAA Rating: PG-13 for disturbing images, sequences of terror, thematic elements and language including some crude sexual references

Cast: Joey King, Julia Goldani Telles, Jaz Sinclair, Annalise Basso

Credits:Directed by Sylvain White, script by David Birke . A Screen Gems release.

Running time: 1:33