This movie is based on the myth of the kappa, the legendary Japanese river imp who is sort of a humanoid turtle about the size of a monkey with a bowl in his head that holds water. Water is the source of life for a kappa and if the bowl is drained it will die. Kappas were very much believed in and were blamed for drownings and other unfortunate events. The majority of the movie takes place in a flashback to a farm in 50's where a boy comes face-to-face with a couple of kappas and discovers they're actually some kind of outer space alien. I did not like the monster design in this movie at all. It is far from the traditional depiction of a kappa, which is kind of cute. They don't have turtle shells or head bowls. The kappa aliens have pretty creepy bodies, they almost look like the aliens from the movie Alien in silhouette. They have frog-like skin and their heads are these gigantic sacks. They are so ugly it is hard to stand looking at them. The music in this movie is good and it's very well photographed, even though the plot is kind of silly. But the look of the aliens ruined the whole movie for me.
Review by incrediblemeltingman from the Internet Movie Database.