Abura Akago, meaning "oil baby" is a mythical creature or yokai from the Omi Province of Japan. They typically appear as an orb of fire, but can transform into the shape of a human child. They start out as a fireball, which floats around until it comes to a house, at which point they enter and change to their humanoid form. They then lick the oil out of lamps or paper lanterns, then turn back into fireballs, and move on to the next house.
They are believed to be the ghosts of people who went unpunished after stealing oil in life, and were unable to pass on to the next life.
Oil was very expensive in Japan at around the time the Abura Akago was believed in, so it could be devastating it to lose to this creature.