‘Come Play’: Digital demon stalks a little boy in wonderfully twisted horror movie

The communication device has long been a key element in horror movies, from “When a Stranger Calls” (1979) to “Scream” (1996) through “Unfriended” (2014) and “Cell” (2016), and the conceit is taken to the next level in “Come Play,” in which a talking monster named Larry is basically trapped in the world of laptops and tablets and smart phones and digital TVs, just waiting for an invitation to slither into the real world and snatch up your child.

Might have you rethinking that whole family package deal you’ve been considering.

I wouldn’t have been surprised to learn “Come Play” was based on a Stephen King story — it has that kind of wonderfully twisted vibe — but in fact it’s the brainchild of writer-director Jacob Chase, expanding the concept he first explored in 2017 in a five-minute short titled “Larry.” Turns out that demon seed of an idea is well-suited to a feature-length film featuring a tension-mounting buildup, some genuinely effective sudden scare moments and a denouement that’s satisfying, moving — and a little crazy. (Not to mention leaving room for a possible sequel, as about 99% of horror films do.)

Young Azhy Robertson does a remarkable job as Oliver, a non-verbal autistic child who communicates through a smart device voice app that allows him to type basic commands and responses. What with an adult helper by his side in the classroom, regular therapy sessions with a counselor who doesn’t seem all that good at her job, no real friends and parents who are on the verge of separating, it’s no surprise Oliver is most happy and comfortable in his bedroom. Surrounded by fantasy action figures, feeling safe in this cocoon, Oliver gets lost in the world of his drawings (kids in horror movies are often creating drawings that should raise alarm bells) — and watching his favorite show, “SpongeBob SquarePants,” over and over and over. And over. (I’m trying to imagine the pitch to the “SpongeBob” people. Not that the show comes off in a bad light — not at all. It’s just a strange juxtaposition to see this famously sweet and silly show as a constant theme in a horror movie little kids should definitely NOT be allowed to see.)

Gillian Jacobs is Oliver’s mother, Sarah, who is near the breaking point after years of devoting nearly every waking moment to caring for Oliver, and John Gallagher Jr. is Oliver’s father, Marty, who works two jobs and is rarely home and seems more than a little disconnected from the reality of the family dynamic — but becomes the instant hero when he walks through the door with a present or a tickle-monster attack. Sarah and Marty are so consumed with their crumbling union and various other issues, they’re oblivious to Oliver’s introduction to Larry, which occurs when an e-book titled “Misunderstood Monsters” keeps popping up on Oliver’s phone. “This is Larry,” the story begins. “He gets made fun of because he is different. Larry just wants a friend.” Just like Oliver, who gets made fun of because he is different, and just wants a friend.

Larry is right out of the movie monster playbook — a creepy, twisted-limbed, hideous-looking creature who speaks in a grotesquely scary voice — but then again, you could have said that about “E.T.” With his parents fighting over him and his classmates bullying him and the real world seeming like an increasingly terrible place, Oliver begins to consider whether he should accept Larry’s invitation to take his claw-like hand and escape into another dimension. Now that’s some good horror movie stuff right there.

Writer-director Chase is clearly a student and fan of scary movies, and he’s not shy about indulging in familiar yet effective clichés, right up to a scene where Oliver and his mom hide under the bed, because of course Larry will never think to look there. There’s a terrifically entertaining sequence late in the film that plays like an homage to a certain element of the original “Poltergeist,” and a thrilling and nerve-wracking extended final sequence that will put you on the edge of the proverbial seat. Gillian Jacobs and Azhy Robertson deliver empathic work as a mother and son who love each other more than anything, though neither knows exactly how to express that. It might just take a monster to clarify things.