Charold is a character in Super Paper Mario who lives in The Underwhere. Charold charges four coins to ferry Mario (and others) across the River Twygz. It is not needed to pay Charold, for Mario could just swim across the River Twygz. Although, it is slightly safer to ferry with Charold, because there is no chance for an Underhand to damage you. However if you stick to the top of the river this should not be an issue anyway. When speaking, Charold draws out his "s" sounds ("ssss").
Charold is named after Charon, the farrier of the Underworld as told by Greek Mythology.