Keukegen is a creature illustrated in Toriyama Sekien's Konjaku Hyakki Shūi

Konjaku Hyakki Shui

is the third book of Japanese artist Toriyama Sekien's Gazu Hyakki Yakō series, published ca. 1781. These books are supernatural bestiaries, collections of ghosts, spirits, spooks and monsters, many of which Toriyama based on literature, folklore, and other artwork...

. It resembles a small dog covered entirely in long hair. Its name is a pun - when written with different kanji (希有怪訝), keukegen means "an unusual thing which is rarely seen".

According to one report, the keukegen is a disease spirit which lives in damp, dark places and causes people in the house to get sick.