An Abura Sumashi is a type of ghostly yokai that haunts mountain passes and other remote areas, described as an ugly humanoid with large heads akin a potato or a stone.
Abura Sumashi are considered very rare and largely harmless to humans, though they may frighten those who stray nearby and are believed to be the ghosts of oil-thieves, who are punished for their crimes via being eternally turned into yokai (there are many such "oil-thief" ghost yokai in Japanese folklore, as stealing oil was considered an extremely taboo practice in ancient Japan and those found guilty would be driven away, often to die in shame and isolation).