“Slender Man” bravely goes against the well-established notion that scary movies should be scary.

It’s a bold move. And an unintentional one: Director Sylvain White is in there plugging away with the jump scares and the moody atmosphere and the found footage, doing everything he can to frighten the audience. But he and screenwriter David Birke can’t come up with anything particularly compelling about the title character, the subject of viral urban legend and creepy stories (as well as the inspiration for real-life crime among teenage girls).

In a nice touch, the film gives a “based on a character by” credit to “Victor Surge,” the name Eric Knudsen used when he entered a Photoshop contest in 2009 and created Slender Man. The character took off online, inspiring horrific stories of a tall, thin, faceless man-shaped creature who terrorizes, harms and sometimes abducts children.

It’s a natural inspiration for a horror movie. Too bad the film itself isn’t much.

It focuses on four girls, Wren (Joey King), Hallie (Juila Goldani Telles), Chloe (Jaz Sinclair) and Piper (Annalise Basso). When we first meet them they’re doing dopey high-school things: flirting with boys, planning a big night out and spending it downing secret vodka and messing around online. The guys they like are elsewhere; supposedly they are going to summon Slender Man. Hallie, the brains of the operation, has never heard of him, but after the briefest of explanations the other girls convince her to play along.

They watch a video that teaches them how to conjure the creature; it involves hearing three bells, the sound of which — distorted and mournful — are the creepiest thing about the movie. Kudos to the sound department.

The next thing you know, the girls suffer nightmares in which they see Slender Man. And then, on a field trip to a cemetery (!) Piper goes missing. Her friends are naturally upset, as is Piper’s alcoholic father, who breaks into Hallie’s house and menaces her, drunkenly demanding to know where his daughter is. So presumably the parents are also upset, although they play about as big a role in the film as adults do in a Charlie Brown special. (No trombone voice sounds, though.)

This leads to Internet research and really bad decision-making on the part of just about everyone, even Hallie. Everyone’s acting weird and seeing things, and they think, thanks to AN ANONYMOUS PERSON ON THE INTERNET, that the only way they can get Chloe back is to go out in the woods and summon Slender Man again. (And to take and destroy things they love.)

And for the first time in history, advice someone gets on the Internet turns out not to be sound.

Again, everyone is trying really hard here. And it shows. Luca Del Puppo’s cinematography is suitably creepy, as befits an urban legend that started out as a purposely grainy photograph. The actors scream and look afraid. There are a couple of cool scenes where they follow the movements of Slender Man on their phones — and he’s coming right for them.

But the movie is a big disappointment, because ultimately Slender Man does not get the full-on creep-out treatment such an intriguing character deserves. Here he’s just a generic horror bad guy, doing standard horror-bad-guy things. He could be anything, really, and therefore winds up, like the movie, being not much.

‘Slender Man’

1⁄2

Screen Gems presents a film directed by Sylvain White and written by David Birke. Rated PG-13 (for disturbing images, sequences of terror, thematic elements and language including some crude sexual references). Running time: 93 minutes. Opens Friday at local theaters.