"Bou" is a male side character from Sen to Chihiro no Kamikakushi. He is Yubaba's son, and in his true form appears as a giant baby wearing a red dudou with his name on it. For much of the film he is transformed into a plump mouse who largely moves around by means of being carried by the transformed fly-like version of Yu-Bird, for whom he develops an affinity towards and is usually paired with.
