Abura-akago

Abura-akago (油赤子, Abura-akago? "oil baby") is a creature illustrated in Toriyama Sekien's Konjaku Gazu Zoku Hyakki, as an infant spirit lapping oil out of an andon lamp.

Sekien's accompanying notes describe it:

In the eighth town of Ōtsu in Ōmi ("Afumi") Province there exists a flying ball-like fire. (近江国　（あふみのくに）　大津の八町に玉のごとくの火飛行　（ひぎやう）　する事あり。, In the eighth town of Ōtsu in Ōmi ("Afumi") 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 of the Ōtsu crossroads, but when this person died his soul became a flame and even now they grow accustomed to this errant fire. (土人云、むかし志賀の里に油をうるものあり、夜毎に大津辻の地蔵の油をぬすみけるが、その者死て魂魄炎となりて今に迷ひの火となれるとぞ。, 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 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. (しからば油をなむる赤子は此ものの再生せしにや。, If it is so then the baby which licks the oil is this person's rebirth.?)
Sekien seems to have have based this illustration on a story from the Shokoku Rijin Dan (諸国里人談, Shokoku Rijin Dan?), in which an oil merchant from Ōtsu steals oil from a Jizō statue at the crossroads, and is punished posthumously by being transformed into a wandering ghost-fire.