Gumiho

The fox spirit of Korean tales. English Wikipedia says the word first named a magical fox in Joseon dynasty novels, and in modern Korea it covers every fox spirit in traditional sources.

Fox spirits appear in old Korean tales. The Encyclopedia of Korean Culture retells the story of the archer Geotaji, who shoots a monk. The monk becomes an old fox, falls to the ground and dies. In thanks, an old man asks Geotaji to marry his daughter, changes her into a flower that Geotaji carries against his chest, and orders two dragons to guard the envoys' ship so it reaches Tang safely. The tale calls the creature an old fox.

A 1913 English translation by James S. Gale of tales by Im Bang and Yi Ryuk explains the idea behind such foxes. The tortoise, deer, crane and fox were thought to live long and grow spiritually refined. A fox that lived long enough could change its shape and appear in many forms, though it could never become a spiritual being the way a person could.

English Wikipedia says the word gumiho first meant a magical fox in Korean novels of the Joseon dynasty. Historical records from the same period also used the word as an insult for treacherous officials. In modern Korea the name has widened to cover every fox spirit in Korea's traditional sources, so gumiho now serves as an umbrella term.

The Korea Herald wrote in 2020 that the drama Tale of the Nine Tailed gave actor Lee Dong-wook the part of a nine-tailed fox, a gumiho. Earlier drama versions of the creature had been played by women, so a male gumiho set this one apart.