Character from the discworld series. Failed wizard, who carries one of the eight most powerful spells in the world in his mind. Only trouble is, he doesn`t know how to use it. AND that`s the only spell he can learn.
Very popular book series by Terry Pratchett, about a world shaped as a disc, that is carried by four elephants who again stands on the back of a gargantuan turtle. The discworld is home to many strange people, like Rincewind