衣蛸
ころもだこ

Translation: cloth octopus
Habitat: Sea of Japan; particularly near Kyōto and Fukui Prefectures
Diet: carnivorous; feeds on both tiny plankton and large ships

Appearance: Koromodako are strange and terrifying octopus-like yōkai. They live in the seas bordering Kyōto and Fukui Prefectures, particularly in the bays of Ine and Wakasa. Koromodako appear similar to ordinary small octopuses. Males only reach a size of a few centimeters long, while females can grow up to five times that length. Being so tiny, they are subject to the tides and waves, and float wherever the currents take them. Females live inside of a paper-thin shell, while males have no shell (similar to the family of octopuses called argonauts).

Behavior: When koromodako are threatened, they become dangerous. They can instantly grow to many times their original size—large enough to engulf fish, fishermen, or any other creature that might try to eat them. Stretching their arms and body out wide, they resemble an enormous piece of cloth, which is how koromodako get their name. While in this form a koromodako can engulf nearly anything in the water, even entire ships. It wraps its arms and mantle around the ship, sailors and all, and drags it down into the deep, never to be seen again. After feeding, the koromodako shrinks down to its tiny size, impossible to trace.