A nifty little monster movie with post-modernist touches that both add and detract from its effectiveness, writer-director Bong Joon-ho’s The Host gets right to the good stuff. After a quick introduction to Gang-du, who works at his family’s food stand (sort of a mini 7-Eleven), and his spunky young daughter Hyun-seo, the movie shifts immediately to a strange sight nearby, drawing a crowd to the bank of Seoul’s Han River: something is hanging off a bridge right in the middle of its span.

Suddenly, it drops into the water, swimming, and the excited crowd watches its approach. They start to throw food – and cans of beer – at the shape in the river. But when that shadow comes to the surface, the playful tone shifts, and the film quickly gets scary as hell: the shape is not the least bit friendly, and it immediately starts chasing, and eating, humans.

The Korean title translates as Creature, and indeed the creature is the single most accomplished thing in the movie: a co-creation of two special effects houses, The Orphanage (Harry Potter and the Goblet of Fire, Superman Returns) and Weta Workshop (The Lord of the Rings). This very frightening beast is part giant cockroach, part carnivorous tadpole, with the terrifying multiple fanged mouths of Alien’s alien, plus a really long tongue. Whenever It is on screen, or even threatening to appear, this is a splendidly effective scare picture.

But Bong Joon-ho has other things on his mind. The store-owning family members are a vivid group of eccentrics, and they become outlaws on the run after one of them is snatched by the creature and the authorities refuse to help them rescue her. The family escapes from the quarantine that has been imposed, and ventures out to find the monster’s lair. The American title, The Host, is ironic: the behavior of the police and the national health officials is handled with sometimes bitter satire, as they come to the conclusion that the creature has introduced a deadly new virus into the world. The authorities (and a mob of conformists following their orders) become co-villains in the story – but they act out of blind stupidity, while the creature itself is only doing what comes naturally.

In its mix of superb film craft with sophomoric jokes, slapstick, shocking violence and sometimes satirical social commentary, The Host reminds me of another recent movie from Korea, Park Chan-wook’s Lady Vengeance. The disparate elements don’t always gel, and American genre fans expecting an ordinary sort of action picture are likely to be unhappy with some of the odd, and sad, plot twists – but after seeing either The Host or Lady Vengeance, you know you’re in the presence of a major talent. (Both of these movies played at the New York Film Festival, and roused crowds accustomed to rather more sedate fare. Bong’s earlier film, Memories of Murder, available on DVD, is also a genre picture with downbeat twists, and it has some interesting similarities to, and differences from, the new film Zodiac.)