Any reasonable creature feature worth its bones should have, on balance, about half a dozen scenes where a character makes a patently illogical decision. Just discovered a new form of ancient alien life? Give it some zaps with a cattle prod, just to see what happens. Now you’re fighting an alien enemy in an enclosed space station? Break out the flamethrower! Running low on fuel? Definitely vent everything you have left in an effort to startle the creature, even when it doesn’t work the first three times. If the film is scary and chaotic enough, every bad choice will act as a link in a chain, building to a satisfying crescendo of mayhem that the audience has secretly been rooting for all along. Life isn’t perfect—you probably won’t remember it after three months—but it does exactly that.

Daniel Espinosa’s horror film is set in space and has some ostensible sci-fi trappings, as it’s centered around humans’ first encounter with prehistoric Martian life. But the movie might as well take place in an underground cavern or a fantasy dungeon, since its two-fold premise is fairly universal: The heroes are trapped in a gilded tomb from which they may not escape, and the monster they’ve awakened is stuck in there with them. Life is gross, full of startling jumps, and is well-performed by its nicely stacked ensemble. In other words, if you’re looking for a competent Alien knock-off or just a way to kill a couple hours, you could do far worse.

Set on the International Space Station, Life sees an appropriately global cast retrieve a probe from Mars that contains special samples from the planet. British scientist Hugh Derry (Ariyon Bakare) revives the frozen, microscopic organism, which gets named “Calvin,” an appropriately stern, theological namesake for mankind’s first extraterrestrial encounter (though Calvin quickly turns out to be more of a cartoonish mischief-maker). At first, Calvin seems friendly enough—even though he grows quickly, he resembles little more than a translucent muscle, a gooey bit of tissue for Hugh to prod with his lab tools.

But as you might have already guessed from the film’s R rating and the amount of f-bombs being dropped (mostly by the energetic Ryan Reynolds, who plays the crew member Roy Adams), this isn’t an E.T.-esque, family-friendly film. After a lab accident seems to drive Calvin back into hibernation, Hugh tries to wake him up with electric shocks; Calvin responds by growing in size again, wrapping his shiny tentacle body around Hugh’s hand, and crushing it. It’s at this point that the dominoes start falling—that the level-headed crew starts panicking in their efforts to save their friends and contain the threat—and Espinosa kicks the action into a high gear he never shifts down from.

The rest of the cast includes Jake Gyllenhaal, as the ISS’s twitchy pilot David Jordan; Rebecca Ferguson (so luminous in Mission: Impossible — Rogue Nation) as the “quarantine specialist” Miranda North; and the great Japanese star Hiroyuki Sanada as the composed scientist Sho Kendo. Sanada is a familiar face for the “doomed space mission” movie—he was the stoic captain of Danny Boyle’s severely underrated drama Sunshine—and he brings appropriate gravitas to a film that’s otherwise heavily reliant on its heroes screaming in pain and distress as Calvin continues to grow and impose his strangling terror all over the space station.

As a threat, Calvin is even less complex than the skittering face-hugger in that great work of sci-fi horror Alien (to which Espinosa is clearly indebted). Even as Calvin becomes larger, he remains a slippery tendril who creates havoc merely by squeezing his targets (and, if he’s feeling really ambitious, jumping down their throats). Given that, it’s impressive just how much inventive, gory fun Espinosa and his screenwriters Rhett Reese and Paul Wernick (both of whom worked on Zombieland and Deadpool) have with Calvin. As the action proceeds, the plot switches from “How do we kill this thing?” to “How do we make sure it never touches Earth’s surface?”

Even as the characters continue to make silly, human mistakes in their efforts to keep Calvin from getting bigger and invading new parts of the station (spoiler: He keeps doing both), it’s hard not to sympathize. Gyllenhaal, slightly slumming it in serious-B-movie territory, is particularly suited, giving Jordan that haunted-weirdo vibe the actor so specializes in. He makes Jordan’s near-suicidal efforts to keep Calvin from crashing the ISS onto Earth feel strangely personal, rather than abstractly noble. All in all, Life is exactly what you’d expect—a bit of nasty, energetic horror that ends on a darkly satisfying note—but that’s an increasingly rare quality for a big-budget studio film these days.