I've always been interested in how certain elements enter popular thought. Recently I think I've traced how a peculiar concept entered the field of Fantasy, and this is how I think it happened.
Walt Disney came out with its animated version of Sleeping Beauty in 1959. In that film, the evil fairy Maleficent is served by a batch of "goons" who search for the baby Princess Aurora and imprison Prince Philip.Among the goons and memorable for having a speaking part is a green, anthropomorphic pig-like character carrying an axe (far right).
Another race of green, piggish axe-wielders came along in The Return of the Jedi (1983), the Gamorrean guards. There was some mild controversy among fans that the design had been snitched from Sleeping Beauty.