The Wawel dragon appeared in a cave in the Wawel Hill in Cracow during the reign of the legendary king Krakus. It demanded the weekly offerings of cattle or, according to other legends, of young girls. He was killled by a deception - a skin of a sheep filled with sulphur was left nearhis cave instead of the real animal. He ate it and either the sulphur started to burn and then tore the dragon apart, or the burning in it’s guts was so strong that it run to the Wisła river and drank so much water that it explode.
According to the various verion of a legend it was either one of the king’s son who came up with the idea of sulphur stuffed sheep, or the king himself, or a poor shoemaker Skuba.