In most Japanese homes there is a large ornate wooden shrine called a butsudan. Inside are religious icons, scrolls, mantras, statues, and other holy items. It serves as the center of household spirituality, and the ancestors of a family are all enshrined in it. During the day, the butsudan stays open, and during holidays and special occasions it is treated like a member of the family, with offers of food and sake given to it. The doors to a butsudan are always closed at sunset; the butsudan is a gateway to the spirit world, and superstition warns that if it is left open at night, certain spirits can wander freely back and forth between the land of the living and the land of the dead. Nuribotoke is one of these spirits.

According to Japanese belief, Nuribotoke is a kind of grotesque zombie which creeps out of a butsudan that has been accidentally left open at night. It is a soft, flabby corpse-like spirit with oily black skin and a pungent smell. Trailing behind is a catfish-like tail connected to its spine. The most striking and disturbing feature is this spirit’s eyeballs, which dangle wildly from its eye sockets.

Nuribotoke do not do much other than fly about, flapping their tails, and terrorizing the families whose butsudan they crawled out from. They dance about impishly, reveling in their ability to terrorize the living. Occasionally they try to trick foolish humans by giving false prophecies. They can be kept at bay by sprinkling salt on the floor, which they will avoid crossing. Nuribotoke return to their butsudan before sunrise, and they vanish altogether during the day. However, it is best to prevent their appearance altogether by never leaving a butsudan open at night.