"Bou" is a male side character fromSen to Chihiro no Kamikakushi. He isYubaba'sson, and in his true form appears as a giantbabywearing a reddudouwith his name on it. For much of the film he is transformed into a plumpmousewho largely moves around by means of being carried by the transformed fly-like version ofYu-Bird, for whom he develops an affinity towards and is usually paired with.