They had forbidden anyone from entering the field except for the one who must check the area around the hut.
The stench permeated the air even this far away, which makes your stomach churn. Why anyone would go near is beyond you.
You exit your house and find the elder waiting. You are to check the hut.
When you near the field, you cover your nose and mouth with cloth. It will keep out the stench -- barely. Approaching, you gag at the smell of rotting flesh. Then you it. Footprints circling the hut.
You rush around to the other side, and stop. There on the ground the monster lay dead.
This is how to kill a Suiko. They are not Kappa, but they are related to them. Suiko translates to water tiger.
They are more aggressive and have control of kappas, sort of like a mid level boss of mafia thugs, which means they have a hierarchy as do the kappa. They report to Ryū-ō, the dragon king.
They have growths on their knees that resemble tiger paws.
These water goblins don't go after the shirikodama, aka the human's small anus ball. (No joke. Kappa may find it in the way of getting to the liver or something. They may even want it. Plus, waterlogged dead bodies sometimes have pooched out bumoly holes.) Nope, these bad boys like to suck the blood out of a human and eat the reikon (soul).
They only way known to kill them is to put the dead body on a plank and in a hut of grass and straw and let the corpse rot. The Suiko has no choice but to be drawn to their victim and will race around the hut until the corpse rots enough that the creature dies. It is said that it is can become invisible until it dies.