Brian Truitt

USA TODAY

Like Jack Black, Comic-Con is going to be feeling some Goosebumps.

The annual extravaganza of movies, TV shows, comic books and pop culture's finest officially begins Thursday at the San Diego Convention Center. And a sneak peek at clips from the family-friendly film, based on author R.L. Stine's Goosebumps anthology series, kicks off four days of geek-worthy entertainment for more than 125,000 attendees. The movie wrapped production in Atlanta on Friday and will be in theaters Aug. 7, 2015.

Instead of simply adapting one of Stine's popular horror-fiction tomes, director Rob Letterman's Goosebumps conceit takes a bigger-picture approach.

Teenage Zach (Dylan Minnette) moves from New York City to a small town, and finds himself intrigued by Hannah (Odeya Rush), the girl next door, but weirded out by her misanthrope father. He is R.L. Stine (played by Black), and he has a big secret: All the Goosebumps monsters come from his imagination and can manifest themselves in reality.

Things get hairy when giant praying mantises, frightful zombies and all sorts of other kooky characters and creatures run wild at night through the local high school football field and the rest of town, and Stine has to come out of his introverted shell and team with some youngsters to save the day.

"He has to put all these monsters back in the books," says Letterman, "and at the same time keep the next-door neighbor kid from dating his daughter.

"It's an incredibly delicate tone to weave horror scares and comedy and adventure," he adds. "I lean on Jack a lot to bridge those gaps."

The genre mash-up was appealing for Black, as was playing a character who looked and sounded very different from himself.

The fictional Stine is "someone with a little more gravitas, a respected writer, a writer with a dark side," the actor says. "So I worked on his voice and I decided to give him an Orson Wellesian accent, a little Northeastern flavor."

The culprit behind all the monsters getting loose is Slappy, an evil ventriloquist's dummy who gets around in a haunted car. He also bears more than a passing resemblance to Black — Slappy is a piece of Stine's subconscious mind come to terrifying wooden life, according to Letterman.

Black has starred in two of the director's projects — Gulliver's Travels and the animated Shark Tale — but Goosebumps "really felt like the movie that he was born to make," the actor says. "He had such a connection to the creatures, and I could see in his face that this was going to be a home run."

Instead of setting out to make a monster movie, though, Letterman says he just wanted something like the films he loved as a kid.

"I love the idea of just starting in a grounded world, and letting a supernatural element enter it — and staying with the characters and seeing how they deal with something impossible to imagine."