The Long Neck Woman or Rokurokubi look like normal human beings by day, but at night they gain the ability to stretch their necks to great lengths. They can also change their faces to those of terrifying oni (Japanese demon) to better scare mortals.
In their daytime human forms, rokurokubi often live undetected and may even take mortal spouses. Many rokurokubi become so accustomed to such a life that they take great pains to keep their demonic forms secret. They are tricksters by nature, however, and the urge to frighten and spy on human beings is hard to resist. Some rokurokubi thus resort to revealing themselves only to drunkards, fools, the sleeping, or the blind in order to satisfy these urges. Other rokurokubi have no such compunctions and go about frightening mortals with abandon. A few, it is said, are not even aware of their true nature and consider themselves normal humans. This last group stretch their necks out while asleep in an involuntary action; upon waking up in the morning, they find they have weird dreams regarding seeing their surroundings in unnatural angles.
According to some tales, rokurokubi were once normal human beings but were transformed by karma for breaking various precepts of Buddhism. Often, these rokurokubi are truly sinister in nature, eating people or drinking their blood rather than merely frightening them. These demonic rokurokubi often have a favored prey, such as others who have broken Buddhist doctrine or human men.
Shirime – Eyeball Butt
In old times, this was a yokai found on the roads leading to Kyoto. The legend goes that late at night, a samurai walking down the street when a man in a kimono stepped in to block his path and said “Excuse me … just a moment of your time … “ The samurai readied himself for an attack, and shouted back “What do you want?”
The man suddenly shed his kimono and stood stark naked. He then bent over and showed his ass to the samurai, which had a single, huge eye. When the eye opened, it shown with a bright light. The samurai screamed with fright and fled from the mysterious monster.
The poet and artist Buzon included the shirime in his collection “Buzon’s Yokai Picture Scroll” (蕪村妖怪絵巻), which is the only known source of the story. It is a variation of the nopperabo legend, and the shirime is considered to be a type of nopperabo.