In Japanese folklore, a kamaitachi is a weasel-like yōkai said to cut people with invisible sickles.
The name is often written with characters meaning “sickle weasel.” Legends describe a group of three creatures that work together: one knocks a person down, another cuts the skin, and the third treats the wound. In some regional explanations, sudden painless scratches or cuts were attributed to the creature rather than to an ordinary accident.
Kamaitachi stories are strongly associated with cold northern winds and winter conditions, especially in parts of central Japan. The term is also used for the dust-devil phenomenon called tsむじ風 in some discussions, although folklore and modern popular culture give the yōkai many forms. It is not a tanuki, kitsune, or tengu, each of which has separate traditions.