Koromodako

Sources do not record a mythic birth narrative. Koromodako is presented in regional folk accounts as a named coastal yōkai used to explain sudden maritime misfortune — a small octopus-like being that appears innocuous but expands to enclose boats and people. Tokihiko Ōtō (1949) is cited as identifying Sodeshi village on the northern tip of the Tango (Yosa) Peninsula as a locality for this lore.

Typically described as appearing in the guise of a small octopus, sometimes concealed inside a shell. One account quantifies its expanded form as covering the area of six tatami mats (given as 12 x 12 Japanese feet square, or about 142.3 sq ft / 13.2 m2). The name (koromo/衣 'clothing' + dako/蛸 'octopus') evokes an octopus that behaves like a garment or covering.

Primary behaviour described is dramatic expansion: the koromodako appears small and then spreads out like a piece of clothing or a bedcover to enwrap boats and people, causing vessels to sink and individuals to be overwhelmed. Some accounts note the creature may hide inside a shell before acting. Sources compare the folkloric motif to real expanding-membrane octopuses (the common blanket octopus, murasaki-dako) which in some localities are also called koromo-dako, indicating a folk comparison rather than a definitive biological identification.