Traveling monk form of an old konnyaku tuber that fears ash
Konnyaku-bozu
"Is there ash in the bath?" The question reveals the monk. One handful of ash in the water, and the pilgrim becomes a single tuber.
Overview
Konnyaku-bozu is a yokai from the mountains of Wakayama. An old konnyaku tuber from a temple field lives many years and turns into a traveling monk, even learning to chant sutras.
Encounter
It visits a remote temple at night seeking lodging. When offered a bath, it repeatedly asks whether any ash has been put into the water.
Lore
The tale appears in Wakayama mountain folklore as Konnyaku no Morai-buro and related stories, where a konnyaku tuber grows old and changes into a monk.
Traits
Its weakness is ash: konnyaku sets when cooked with ash, so if ash is thrown into the bath, the monk form collapses and only a konnyaku tuber floats in the tub.