A thoroughly unusual kind of monster movie from Korean director Bong Joon-Ho, who brought us the thoroughly unusual detective tale Memories of Murder in 2003 and is still only 37.

This one isn't as intense and thoughtful as its predecessor, but it does combine adept CGI and real footage to create an extraordinarily vivid giant lizard/tadpole monster. The action scenes are visceral and the film has broken box-office records in the thriving local industry.

Toxic contamination is to blame, as with the Japanese hero Godzilla, and many others since. But unusually, this is based on reality: the prologue implicitly blames an incident in 2000 when a military employee put formaldehyde into the Seoul sewer system.

The plot, of a disparate family coming together to fight the beast that has carried off its star member may also have some basis in the unbelievable but true story of North Korea kidnapping a South Korean director and actress to work across the border in the 70s. The film Kim Jong-Il had them make was a Godzilla-style movie, Pulgasari: The Legendary Monster.