In Japanese mythology, mokumokuren (目目連) are yōkai (妖怪, ghost, strange apparition) spirits that usually live in torn shōji (sliding paper walls), but they can also be found in tatami (floor mats) and in walls.
The name mokumokuren literally means "many eyes" or "permanent eyes". The mokumokuren is considered by the Japanese as one of the traditional inhabitants of haunted houses. The only way to remove the spirit from the wall is to fill the holes.
The mokumokuren is said to be an invention of Toriyama Sekien.
Legends about mokumokuren
A miserly traveling merchant once tried to save money by sleeping in an abandoned house instead of an inn.
Waking up in the middle of the night, he was confronted by (almost) the entire screen of a shōji with its eyes fixed on him. Instead of getting scared, he removed the eyeballs from the screen and sold them to a local eye surgeon.
In another story, a traveler determined to stay in the same house as a mokumokuren, tries to ignore it by wrapping the blanket he sleeps under tightly around his head.
When he wakes up, he discovers that his eyes have been removed and cannot find them. Perhaps his eyes had joined those already buried in the mokumokuren.