Kitsune-tsuki (translated variously as "fox-madness", "fox-possession", and "fox-lunacy"), in Japanese mythology, is a state of madness in which one is posessed by a wild fox spirit, which enters the body through the breast or the space under the fingernails. Those afflicted with kitsune-tsuki, frequently women, may have cravings for rice or sweet red beans, which are the traditional favorite foods of foxes, and may appear listless or restless and avoid eye contact. The idea that fox spirits could possess humans originated in China, where the "Fox Fairy" is feared and revered; Chinese folklore states that possession is often punishment for wrongs against the fox spirits, though a fox spirit may possess someone simply out of a capricious desire to do so.
The possessed are traditionally said to have special powers; for instance, the Japanese tradition states that possession temporarily grants literacy to an illiterate person, and the Chinese tradition records that possessed humans can pass through walls and fly, among other things. The spirit is said to rest in the left side of the torso, or in the stomach. The consciousness of the possessed person and the inhabiting fox spirit continue to be separate and are said to have frequent arguments, but their voices differ distinctly.
In order for the fox-spirit to be exorcised, a priest is summoned, who scolds the fox spirit and negotiates with it so that it will leave the human host. Negotiations often involve gifts of rice, sweets, or other material goods in order to tempt the greedy side of the fox-spirit's nature.
Source: http://www.inari-art.com/kit_info.htm