A young Japanese woman named Kanako returns to her small village after realizing that she has no talent as a pop star. The first two people she encounters are deformed--the train attendant is a hunchback and a storekeeper has a double face, which is sort of weird. Then, upon reuniting with her grandmother, a car full of partygoers runs her over, then hit the mummified remains of a creature--a Kappa--which gets sent into the ocean. You see, the town had worshipped the remains of this "Water Goblin". Before the grandmother takes her last breath she tells Kanako that they have to protect the Kappa. It's a strange creature. It swims, likes Sumo wrestling and loves to eat cucumbers. She prays to her grandmother and promises to protect the man-sized monster.
Meanwhile, the dried body has rehydrated and comes to life. It kills the people who ran over the grandmother, then dances to Kanakos music when a neighbor's kid is playing her music on the radio. Both she an the Kappa are captured by an evil mad scientist. Her grandfather had done experiments during WWII, combining Kappa with human DNA--and these experiment have continued. The lab ends up exploding with a nuclear blast, which unleashes a monster, Hangyolas, on the city. Then, the Kappa appears to battle it--and it's a giant as well.
DEATH KAPPA is a very entertaining Kaiju movie, like a cross between the old ULTRAMAN series and an Adam West BATMAN episode. Recommended if you're in the mood for cheesy monster mayhem.