The Ōnyūdō is defined by its sheer size and piercing glare. Reports range from a monk-like giant with a topknot to a vague shadowy figure, appearing in liminal places such as night roads, temple and shrine grounds, mountain passes, and lakesides. It draws the gaze of onlookers and, the instant they look up, grows taller to assert its might. Explanations of its nature vary by locale: a transformed animal, the spirit of an old stone pagoda or boulder, or an unclassified anomaly. Harmful cases include people collapsing under its stare or developing fever afterward, yet in places like Awa it is also told as a semi-guardian that helps with labor. Countermeasures follow traditional banishment methods: do not fear or avert your eyes, break its menace with arrows or prayer beads, or expose the true form of the shapeshifter. Historical sources sometimes mix names like Ōbōzu and Ōnyūdō, so it is best understood within local traditions.