Sometimes it feels as if there are as many famous yokai in Japanese urban legends as there are heroes in the Marvel universe. When it comes to creepy stories about demons in Japan, the supernatural yokai play both heroic and nefarious roles, depending on the tale at hand. While some yokai exist as horrible demons, others only want to play pranks; some more benevolent yokai even bring good luck. Since no true equivalent of the yokai exists in the West, it helps to think of them more as paranormal-monster-mythological-creature hybrids. Furthermore, certain yokai, like the sometimes vampiric rokurokubi, live as both humans and demons, further complicating the existence of these "monsters."
Yokai appear throughout Japanese folklore, and many of these tales speak of the rokurokubi. These yokai appear in human (and typically female) form during the day, but their head wanders off at night, usually still attached to their neck. While rokurokubi are more pranksters than anything, their kind also includes nukekubi, blood-thirsty demons whose floating heads exude vampire-like tendencies. Along with many other yokai, the history of rokurokubi vampire demons is part of Japanese culture, making them a beloved, and sometimes feared, addition to Japanese legends and your worst nightmares.
Although these yokai can be mistaken for human women during the day, their true form emerges at night. Rokurokubi translates roughly to "long neck," a reference to the yokai's ability to stretch its neck far from its body. The head has a will of its own and wanders wherever and however far away it pleases. While most rokurokubi understand themselves to be yokai, a few still believe they are human. These deluded yokai remain unaware of their body's night antics, and explain away the "visions" they saw in the night as dreams. While rokurokubi most often appear in female form, a few stories exist that feature male versions.
Nukekubi is a type of rokurokubi whose head detaches from its body in order to travel. Roughly translated to "removable neck," nukekubi move without a neck holding them back and thus manage to cover greater distances than rokurokubi. Legend states a nukekubi's soul travels along with the head, making them seem more demonic. Also said to be more violent than their long-necked cousins, the nukekubi reportedly attack humans and drink their blood like vampires. A nukekubi's thirst is sometimes quenched by animals and occasionally they simply bite their victims rather than drinking their blood.
To kill a nukekubi, one must move its body to a safe place where the head cannot return. However, many nukekubi, like rokurokubi, are unaware of or powerless to stop their curse, and therefore friends and family may find it difficult killing off someone they love, even if they're cursed.
Nukekubi, the most violent of all rokurokubi, reportedly attack and kill humans and other animals. Rokurokubi, on the other hand, are more playful and enjoy using their neck stretching skill to mess with people. Simple pranksters, rokurokubi take pleasure in frightening people, scaring small animals, knocking things over, and spying. Rokurokubi also like knocking over oil lamps to drink the oil, and several stories claim the yokai exposed themselves when oil began disappearing from the home at a rapid rate. To keep their existence more secretive, rokurokubi make a point to appear in front of drunk people, who usually are too intoxicated to remember or give credible testimony about what they saw.
While most yokai come into this world as yokai, rokurokubi once lived as humans who became yokai as the result of a curse. According to legend, the curse could happen as a result of several factors. A woman could become a rokurobubi after committing a sin or being unfaithful to her husband. However, if her father, husband, or other family member commits a sin, the curse of the rokurokubi may still inexplicably fall upon the woman . Unfortunately, some even claim the curse passes down from a woman to her daughters.