In Japan there is a vampiric creature that lives in ponds called a kappa ("river child"). It looks like a GREEN child with a long nose, round eyes, tortoise shell on its back, and webbed fingers and toes, and smells like fish. However, its most interesting physical feature is a dent in the top of its head deep enough to hold water. The water that sits in the dent is representative of its power. Should a kappa attempt to attack a person, he must quickly bow to it. As it is a stickler for courteousness and ritual, the kappa will take pause to return the bow. When it does so, the water in the dent will spill out, rendering the creature powerless.
The kappa hunts from its home in the water.It waits until a cow or horse comes to drink and then it pulls the animal down into the water. As the animal drowns, the kappa bites into the animal's anus to drain it of its blood. The only time a kappa will leave its watery home is to steal cucumbers and melons, rape women, and to rip the livers out of people.
The kappa is incredibly strong and a highly skilled sumo wrestler. It is also a skilled teacher in the art of bone setting and medical skills.
It may well be that the kappa is the only vampire that has a cucumber fetish. No matter what may be happening all around it, a kappa will stop whatever it is doing to steal away with one should the opportunity arise. By writing one's family name on a cucumber and giving it to a kappa, the entire family will be temporarily protected from its attacks.
Kappas can be surprisingly courteous, honorable, and trustworthy beings. They are highly respectful of ritual and tradition, even going so far as to challenge one of its would-be victims to a wrestling match. Akappa can even be bargained with, willing to enter into contractual agreements not to attack certain people.
Source: Davis, Myths and Legends of Japan, 35052; Mack, Field Guide to Demons, 1718; Rowthorn, Japan, 511