Shidaidaka

No cosmogonic or origin narrative is recorded in the cited sources; the shidaidaka appears in local oral tradition across multiple Chūgoku prefectures and is presented in those sources as a localized roadside yōkai and as a member of the mikoshi-nyūdō family.

Reported as a humanoid yōkai whose principal and consistently recorded attribute is variable apparent height: it grows when seen from below or when observers look upward, and becomes shorter when looked downward. The sources classify it as a type of mikoshi-nyūdō, but specific mikoshi-nyūdō physical traits (e.g., bald head, extending neck) are not directly described for the shidaidaka in the provided materials (marked as uncertain in the sources).

Primary behavior is perception-dependent change in apparent stature: looking up causes it to grow taller; looking down causes it to shrink and disappear. Regional narratives add variant behaviors: in a Hazumi folktale hunters are advised to reserve a last bullet in case a shidaidaka appears (narrative tactic to kill it), and in a Matsukawa account a shidaidaka is said to be the boss or true form of a nekomata. The sources treat these latter points as local tale variants rather than universal attributes.