According to Japanese belief, Tsurubebi is a type of hi no tama, or fireball yokai. Tsurubebi are small tree spirits which appear at night, deep in coniferous forests. They take the form of blueish-white orbs of fire which bob up and down in the branches, occasionally dropping to the forest floor and floating back up into the trees. Their name (literally "well bucket fire") comes from the way they bob about in the trees, which is supposed to resemble a well bucket swinging back and forth. Sometimes the vague shape of a human or bestial face can be seen in the flames.

Tsurubebi do very little other than bob up and down or drop from branches. Their flames produce no heat and do not burn the trees that they live in; nor do these yokai pose any other known threat. While tsurubebi is most often considered to be a tree spirit, it has also been suggested that it is closely related to another yokai named tsurube otoshi. These two yokai share many similarities, including their names, coniferous habitat, and dropping-down behavior. However, while tsurube otoshi is malevolent and dangerous, tsurubebi appears to be entirely benign and uninterested in humans.