According to japanese beliefs, Furaribi is a small, flying creature wreathed in flames. It appears late at night near riverbanks. It has the body of a bird, and its face is somewhat dog-like. It is a type of hi-no-tama, or fireball yokai. It does very little except for float about aimlessly, which is how it got its name, literally — "aimless fire".

Furaribi are created from the remains of a soul which has not properly passed on to the next life. This is most often due to not receiving proper ceremonial services after dying. In Japan there are a number of important ceremonies performed at fixed intervals which occur for many years after someone’s death — missing even one of these could cause a soul to become lost and be unable to rest. Furaru-bi is one of these lost souls.

In the late 16th century, Toyama was ruled by a samurai named Sassa Narimasa. Narimasa kept a very beautiful concubine named Sayuri in his household. Sayuri was not well liked by the female servants and other women in Sassa Narimasa’s household. They were jealous of her beauty and of Narimasa’s love for her. One day, these women conspired against Sayuri and started a rumor that she had been unfaithful to Narimasa with one of his own men. Narimasa flew in a fit of jealous rage, murdered Sayuri, then took her body down to the Jinzū river. He hung her corpse from a tree and proceeded to carve it into pieces with his sword. Then he captured Sayuri’s entire extended family — 18 people in all — and executed them in the same manner. Afterwards, their tortured souls aimlessly wandered the riverbanks every night as furaribi.

It is said if you go down to the riverside and call out, "Sayuri, Sayuri!" late at night, the floating, severed head of a woman will appear, pulling and tearing at her hair in a vengeful fury. As for Sassa Narimasa, he was later defeated by Toyotomi Hideyoshi. Some have attributed his defeat by Hideyoshi to the vengeful curse of Sayuri’s ghost.