Fool (stock character)
William Wallace Denslow's illustrations for Three Wise Men of Gotham, from a 1901 edition of Mother Goose
The fool is a stock character in creative works (literature, film, etc.) and folklore. There are several distinct, although overlapping, categories of fool: simpleton fool, wise fool, and serendipitous fool.
The six volume Motif-Index of Folk-Literature contains (in volume four) a group of motifs under the category "Fools (and other unwise persons)".