Kamaitachi

Kamaitachi（鎌鼬), or "Sickle Weasel" is the name given to a bizarre Japanese folk tradition.

One of the mysteries of Japan that remains one to this day is that of the Kamaitachi. Many believe in their existence, even scientists and doctors, due to the prominence of these creatures. Oftentimes a traveller will be going through a place, especially swamps and forests, and suddenly and without warning they will be attacked by a force moving so fast it can hardly be seen. The victim is often knocked down swiftly and cut deeply, but the cuts do not bleed very much at all. However, the attacks are sometimes fatal and undoubtedly very painful even if not so serious.

Survivors of attacks who managed to keep their wits about them have consistently reported seeing three weasels rolling through the air, wielding sickles. These are what they use to attack their targets, and apparently they do so with such grace and skill that little blood is actually shed. Another supposition is that they actually heal their victim's wound just enough for it not to bleed excessively, sometimes to attack again.

Very little, however, is actually known about kamaitachi. It is unknown if they have any sort of society or interact with other youkai, and the reasons behind their attacks are equally mysterious. Perhaps they are protecting their territory? There are endless possibilities, and no kamaitachi seem forthcoming to confirm or deny any of them.