The Host
The Host (; lit. "Monster") is a 2006 South Korean monster film directed by Bong Joon-ho and starring Song Kang-ho, Byun Hee-bong, Park Hae-il, Bae Doona and Go Ah-sung. The film concerns a monster kidnapping a man's daughter, and his attempts to rescue her. According to the director, his inspiration came from a local article about a deformed fish with an S-shaped spine caught in the Han River.
Plot
In 2000, an American military pathologist orders his Korean assistant to dump 200 bottles of formaldehyde down a drain leading into the Han River. Over the next several years, there are sightings of a strange amphibious creature in the waterway, and the fish in the river die off.