Abura-sumashi

Abura-sumashi (すまし) is a rare creature from the folklore of Amakusa in Kumamoto Prefecture that lives in the mountain passes of Kumamoto.

Mythology
This spirit, which surprises people on the Kusazumigoe mountain pass, is thought to be the ghost of a human who stole oil and fled into the woods.

In the days before electricity, oil was a very valuable commodity, necessary for lighting and heating a house. As such, it was thought that the theft of oil, particularly from temples and shrines, could lead to punishment via reincarnation as a yōkai.

In many stories an old grandmother walking a mountain pass with her grandchildren will say, “You know, a long time ago, an abura-sumashi used to live in these parts,” and a mysterious voice will call out in reply, “I still do!” Or on rare occasions the abura-sumashi will appear to the travelers, materializing out of thin air.

In modern media the abura-sumashi is often depicted as, "a squat creature with a straw-coat covered body and a potato-like or stony head," an appearance inspired by the artwork of Shigeru Mizuki.