Abura Akago - [yokai]

Abura Akago - [Yokai] - 油赤子 (あぶらあかご)  - "Oil baby"

• About this Yokai: The spirit of an oil thief which appears as a flaming infant or as a fireball, it flies through windows at night to lick up lamp oil out of Andon lamps, it's a "sardine oil" powered ghost baby. 

• History & Early Appearances: Probably best known for its appearance in Konjaku Gazu Zoku Hyakki [1779 by Toriyama Sekien] - it seems that Toriyama based this yokai's story on Shokoku Rijin Dan (Stories of Common Folk – 諸国里人談) an anthology of stories published in the 1740's which included a handful of old yokai stories. - including one about ghost fires! (abura-bo) - Sekiens passage translates roughly as follows: 

- [in Konjaku Gazu Zoku Hyakki [1779]]

"In the eighth town of Ōtsu in Ōmi Province there exists a flying ball-like fire. The natives say that long ago in the village of Shiga there was a person who stole oil, and every night he stole the oil from the 
Jizō statue of the Ōtsu crossroads, but when this person died his soul became a flame and even now they grow accustomed to this errant fire. If it is so then the baby which licks the oil is this person’s rebirth."

At the time, lamp oil would have mostly been handmade and either made of ground up tea leaves or was otherwise fish based. There's a long held theory that perhaps at night, the shadow of a cat drinking the oil could have been mistaken for a small person or a baby. - I'd suppose that might explain why so many yokai (especially bakeneko) where said to to drink it. - It was also expensive to produce, so several yokai have been said to have been oil thieves in life (Such as Ubagabi and Sogenbi.) so perhaps such stories originated as a warning not to waste the oil. - I do like to think that jizo has something to do with this particular equation as well, as traditionally Jizō statues where said to protect children in the afterlife. 

[edo period art of a cat drinking oil out of a lamp, image source]

This yokai also featured on various karuta cards (A testament to widely this story would have been known at the time.)

[image source via Nichibun yokai database.]

• similar yokai: Abura Sumashi, Ubagabi, Sogenbi, Rokurokubi, BakeNeko. 

Art sticker by samkalensky! part of my hyakki yagyo night parade of 100 demons yokai sticker collection! follow & support for many more :)