Suiko

In Japanese folklore the suiko (water tiger) is a yokai that lives in rivers, lakes, ponds and waterways throughout Japan. They have a body that is the same shape and size as a small child and is covered in tough scales with sharp claw-like spikes protruding from their knees. Suiko are far more dangerous than the more well-known kappa. In the hierarchy of Japanese water goblins, suiko rank above kappa and are often in charge of them. The suiko then report to the dragon king and often try to impress him by killing humans. 

Shigeru Mizuki

Suiko pull people into the water to drown them before draining all their blood and eating their souls. They will then return the dead, bloodless body to the surface of the water. Suiko sometimes leave the water and venture into towns to play pranks on humans using their ability to possess people and make them act in strange ways. Suiko's magical powers also include the ability to become invisible. To repel a suiko, you can use either flax seeds or black-eyed peas, but if you want to kill them it will require an elaborate ritual involving a victim's corpse.

Toriyama Sekien