Jason Sudeikis and Anne Hathaway in Colossal.

Anne Hathaway and Jason Sudeikis gloriously upstage two kaiju monsters in Colossal, a science-fiction monster mash that features numerous twists—and a psychological/emotional river that runs mighty deep.

Hathaway outdoes herself as Gloria, a New York City writer who gets kicked out of the apartment of her boyfriend (Dan Stevens) because she is constantly partying and being somewhat “unmanageable.” She winds up in her hometown, sleeping on an inflatable mattress, where she bumps into Oscar (Sudeikis), a childhood friend.

Oscar, an overly sweet and generous guy at first glance, immediately tries to help out Gloria. He gives her a job at his bar and showers her with furniture for her sparse home. This seems to be the setup for a strange romantic comedy—with science fiction/horror as the background.

Writer-director Nacho Vigalondo, however, has something much different in mind.

Gloria awakens one morning after a night of drinking to discover that a giant, lizard-like creature is attacking Seoul, South Korea. After examining some YouTube videos and news reports, she realizes the monster seems to be mimicking her mostly drunk body movements. Yes, the monster is the manifestation of her self-loathing, out-of-control, alcoholic ways, and it’s taking lives in Korea. She feels more than a little bit guilty about this.

Things get weirder when an equally large monster robot shows up next to Gloria’s monster—and appears to be the manifestation of Oscar’s anxieties. Oscar is far more into the notion of having a monster under his control and starts playfully taunting Gloria. The monsters wrestle it out, and their battles become more intense as Oscar and Gloria begin to have ever-bigger problems in their newly reborn friendship.

While the movie has plenty of fun with giant monsters beating each other up, it has even more fun with the mystery that is Gloria and Oscar. It becomes an introspective film, and even a scary look at messed-up relationships—more specifically, severely messed up dudes and their manipulative ways.

Sudeikis is on fire, delivering easily the best performance of his post-Saturday Night Live career. Oscar is as clever and charming; many of his actions seem to be propelled by good-natured ribbing or tomfoolery. As the film goes on, however, Sudeikis and Vigalondo slyly reveal more and more about Oscar’s psyche. It turns into one of the more interesting, intricate character studies in a movie so far this year.

Then there is Hathaway, one of the more wonderful actresses to ever occupy the big screen. There’s been a strange Hathaway backlash since her incredible, Oscar-winning turn in Les Miserables. (Some of that blame is due to her straining attempt at hosting the Oscars while co-host James Franco mentally checked out mid-ceremony.) Colossal immediately re-establishes her as an actress to be reckoned with. She’s everything in this movie: hilarious, heartbreaking, sympathetic and sometimes full-blown crazy. Sure, the manifestation of her problems is killing helicopter pilots in Korea, but we can’t help but root for her. Many of us probably have buddies like Gloria—minus the kaiju shadow, of course.

Together, Hathaway and Sudeikis create fireworks that overshadow their clashing monsters. They prove that human beings going at each other’s throats can be more terrifying than King Kong vs. Godzilla.

By the time it plays out, you’ve seen what will surely stand as one of the year’s more clever, adventurous and experimental films. You’ve also seen the next step in Sudeikis’ career, as he proves he can be a true dramatic force. As for Hathaway, you’re seeing more of the same—an actress in full command of her every moment onscreen in a movie.

What a wonderful, weird, gonzo idea for a film. Colossal goes into the category of movies with Being John Malkovich, Barton Fink and Mulholland Dr. It’s bizarre—but it will have you thinking about it long after you’ve seen it.

Colossal is now playing at the Palm Desert 10 Cinemas (72840 Highway 111, Palm Desert; 760-340-0033). It opens Friday, April 28, at Mary Pickford Is D’Place (36850 Pickfair St., Cathedral City; 760-328-7100).