The term "Gumiho" translates literally to "fox with nine tails." This creature makes numerous appearances in Korean legends and fairy tales, and is similar in some ways to the fairies of European folklore. These legends state that a regular, mortal fox that manages to live for one thousand years becomes a Gumiho, meaning that it can transform (usually at will) into a beautiful young woman who seduces male mortals, and then eats their liver or heart, depending on the version. While they are able to physically transform themselves, their sly nature remains the same.
Gumihos appear to date back centuries, and apparently originated in Chinese legends. They share characteristics with other fox-like creatures in both Chinese and Japanese mythology, though whereas these beings can be good or bad, Gumihos are almost always malevolent creatures. They feed on human livers (some legends state that they eat hearts, instead) in order to survive.
Traditionally the Gumiho is female, and most myths agree that they can fully transfigure into a human woman, though some insist that a single trait remains that betrays their real identity. These range from having the face of a fox, to having a pair of fox ears, to being left with a set of nine tails. Either way, there is always a way to check if a person is truly a Gumiho, or a magical way to force them to admit it.
According to some legends, a Gumiho can become human and permanently remain in this state by not ingesting a human's liver (or heart) for a period of one thousand days. Still others claim that if a man sees the Gumiho assume it's true form and keeps her secret for ten years, she will become and remain human. Despite these differences between tellings, there are qualities that never change: the Gumiho is always a fox, it is almost female, it always has the ability to shape-shift, and it always eats human meat.
One of the myths in which the Gumiho makes an appearance is "Transformation of the Gumiho." It adopts the form of a young bride, and not even the bride's mother can tell that her daughter has been replaced by an impostor. The Gumiho's true nature is exposed only when her clothes are removed that night.
Another such tale is "Maiden who Discovered a Gumiho Through a Chinese Poem," in which the fox-creature is attacked and killed by a hunting dog who caught the scent of a fox on it. In this tale, the Gumiho happens to be male, and when it transforms, it takes on the appearance of a young man, but this is the only case in which this occurs.
Another Japanese fox of mythological origins is Tamamo-No-Mae, who was a courtesan under the Emperor Konoe. This girl was rumoured to be the most intelligent and beautiful in all of Japan, and it was noticed that her clothes never became wrinkled or dirty, and that she always emitted a wonderful scent.
She was able to answer any question on any topic even though she appeared to be no more than twenty years old. She was adored by everyone in the Japanese Imperial court, including Emperor Konoe, who spoiled her with affection and gifts. Soon after meeting her, the emperor fell ill, and no fortune tellers or priests could tell him what it was that was making him sick. Just as he began to panic, he was approached by an astrologer, who explained that Tamamo-No-Mae was a benevolent nine-tailed fox, working for an evil daimyo (or cruel, territorial lord) who was using the girl to make him critically ill in an attempt to take over his empire. When Tamamo-No-Mae was made aware that the emperor knew this, she fled from the court without a trace.
The enraged emperor commanded his most powerful warriors, Kazusa-No-Suke and Miura-No-Suke, to track her down and kill her. After many unsuccessful hunting expeditions, Tamamo-No-Mae appeared to Emperor Konoe for the final time, in a dream. She predicted that his warriors would catch her the following day, and pleaded for him to spare her life. He refused.
Sure enough, the emperor received word that afternoon that his men had finally cornered her, and had shot her through the heart with an arrow. Tamamo-No-Mae's body turned into a large obelisk, known as the Sessho-Seki, or Killing Stone. The Killing Stone is haunted by Tamamo-No-Mae's angry spirit, and anyone who comes into contact with it dies, or so the legend goes.
It is said that a priest by the name of Genno stopped by this stone to rest, and was attacked by the evil entity living inside the structure. He begged the spirit of Tamamo-No-Mae to reconsider what she was doing, and she soon gave in, swearing never to return and haunt the stone again.
The Teumessian Fox
The Teumessian Fox (also known as the Cadmean Vixen) was a colossal fox-being that could never be caught, due to a spell that had been put on it by the god Dionysus. It was one of the children of Echidna, and was sent to hunt down and destroy the children of Thebes as a punishment for a great, but unspecified crime.
Amphitryon was given the task of killing the Teumession Fox, which would have been impossible, due to it's being destined to remain free forever. He was sure he'd solved this problem by requesting the help of Laelaps, a gigantic dog who was bound to catch everything it ever chased.
Confronted with a seemingly unsolvable conundrum, Zeus turned both beasts to stone, and sent them to live among the stars, where they remain to this day. It is said that one day, they may return, though this can only be done with Zeus' blessing.