Ogumo (Giant spider) (大蜘蛛)
Ogumo is a gigantic spider monster which appears in Japanese Kaidan (ghost stories), essays, folk material and so on. It was mentioned in old books such as "Inu hariko" (literally, The Toy Dog), "Shoko-ki" (a collection of ghost stories originated in Tang China), "Mimibukuro" (literally, Ear bag), and "Tonoigusa" (literally, Night watchman's storybook), while in "Tsuchigumo no soshi" (Tale of the ground spider) and "Heike Monogatari" (literally, The tale of the Heike) it is known as Tsuchigumo (literally, ground spider).
Summary
"Sorori Monogatari," a collection of Kaidan of the Kanbun era (1661-1673), has a story titled 'The incident in which a huntsman spider transmuted,' the story of which is that one night the Ogumo took the shape of an old woman of around 60 years old, swinging its disheveled hair, attacked a man who lived in the countryside, and its leg was cut off by his sword.
According to the "Inu hariko," when a yamabushi (a mountain priest) stayed at Daizen-in Temple in Gojo Karasuma, Kyoto, there was a very loud noise late at night, and at the same time, a hairy arm stretched from the ceiling and stroked yamabushi's face, so that the yamabushi cut off the arm, and the next morning there was the dead body of the Ogumo as big as about 84 cm by a Buddhist altar there.
"Shinano Kishoroku" (literally, a topography of Shinano Province, which was written in the Tenpo era (1830-1844) and includes a story of the Ogumo which sucked energy out of a human to make him ill.
In Iiyama, Shimominochi County, Shinano Province (present-day Nagano Prefecture), there was a farm family of the mother and the son, and when the son became ill, he began to suffer saying, 'A spider is coming, it's coming.'
The mother tried to kill the spider, but it seemed that only the ill son could see the spider; and her prayers did not work at all. After a while, maybe because of the mother's deep worry for her son, she gradually became able to see the spider; she held the spider down in the bed, but on the contrary, she was caught in the spider's thread. The neighbors heard the mother's painful groan and rushed to her place and killed the spider to rescue her; it was a gigantic spider which they had never seen before. Although the son managed to survive, his blood had been sucked and many parts of his skin had come off, so that he could not walk without a stick.
One theory has it that these legends of spider monsters came from a folk belief that old spiders would acquire mysterious powers.