Spooks

Nurikabe
The nurikabe was a yokai—a Japanese monster—shaped like a wall that appeared in the paths of travelers. Usually invisible, it would completely impede a road, forcing them to go around it. Like many yokai, though, the nurikabe was a trickster. Even if someone tried a different path, the wall would elongate or inexplicably get up and move. It was said that anyone who encountered a nurikabe could get lost for days.

Zashiki-Warashi
Large houses in ancient Japan were open affairs with rooms separated by shoji screens. Noise would carry and would often seem to come from strange places. When rustling noises or the sounds of footsteps came from an empty room, superstition had it that a spirit called a zashiki-warashi was inhabiting the house.
Roughly translated as “parlor child,” zashiki-warashi were child-like spirits that lived in empty rooms. They were said to be at most 12 years old and would occasionally appear to the house’s tenants. While the noises they made were mysterious and their sudden appearances would probably have given most families a shock, zashiki-warashi were said to bring good fortune and prosperity to whomever they lived with.

Unfortunately, they also took it away when they left. Zashiki-warashi moved from place to place whenever they saw fit. In one story, a family had two living with them who brought prosperity to their household while they were present. Eventually they left, however, and soon after almost the entire family died when the servants mistakenly served them a meal of poisonous mushrooms. The next family that the two zashiki-warashi moved in with, meanwhile, immediately became prosperous. Due to their association with fortune, it’s been theorized that zashiki-warashi were a device used to explain the sudden rise and fall of wealthy families.

Ubume
There could be any number of reasons for the disappearance of a child, but according to ancient Japanese superstition, most missing children were spirited away by a monster called an ubume. An ubume is a bird-like creature that became a woman who kidnapped children once its feathers were plucked. Ubume were believed to be the spirits of women who died in childbirth, though they could also have died while pregnant. Either way, their attachment to their lost child lingered after death and gave them an insatiable need for one of their own, which they appeased by kidnapping one.
Another incarnation of the ubume is a topless woman carrying a baby. Appearing at dusk at crossroads and bridges, the ubume would ask passersby to hold her child while she ran an errand. The baby grew heavier and heavier until the person holding it recited a Buddhist prayer, whereupon the ubume returned and thanked them for bringing her child back into the world of the living. Still other accounts had ubume searching for guardians to care for her baby after her death, while in others she did so herself by making occasional visits into town to buy supplies with coins that turned into dried leaves after she disappeared.

Himamushi-Nyudo
Night work was usually done by oil lamps in ancient Japan. Unfortunately for those who made their living at night, the preferred oil was fish oil, a favorite of both mice and cockroaches. The pests would drink the oil and force the worker to waste time fending them off. Sometimes, though, when the loss of oil was thought to be too much for the critters to have stolen, superstition held that it was taken by a monster called the himamushi-nyudo.

It was said that the soul of a person who wasted all his free time would become a himamushi-nyudo—which roughly means “oil licker”—and interfere with the night work of others. Despite the superstition, the connection to cockroaches was not lost on yokai catalogers, and the monster was often depicted alongside cockroach symbolism. As the insect was once believed to have been born from the cracks in kama, or Japanese scythes, the himamushi-nyudo was often portrayed with cockroaches and other related symbols like mugwort and chickens, which were thought to keep the pest away. This association led to the suggestion of himamushi-nyudo being giant anthropomorphic cockroaches.

Tenjo-Name
Without modern heating and insulation, ancient Japanese houses proved very cold in winter. Those with high ceilings also grew quite dark at night. Superstition held that both winter’s chill and the dark were caused by a monster called the tenjo-name. The creature would float in the upper reaches of the room, bringing down the temperature and obscuring the ceiling. It was a tall, bony creature with a long tongue that it used to lick the ceilings. When the tenjo-name licked the ceiling it became dirtier, not cleaner.

Kamaitachi
That someone could simply fall down from time to time didn’t seem to make much sense to the superstitious Japanese, so they held that people were knocked down by a monster. Kamaitachi, or “sickle weasels,” were packs of monstrous weasels that rode the winds and inflicted cuts and scrapes on innocent human victims.
Moving faster than the eye could see, kamaitachi worked in groups of three. The first would knock the victim down, then the second, bearing the sickles, would slash at them until a third came behind and healed the wounds. The monsters were held responsible for all sorts of tumbles, and after getting up and finding a cut, the victim would exclaim they had been cut by a sickle weasel.