Credit for picture The Questing Beast is one of the mythical creatures mentioned in King Arthur legends. Credit for picture The Questing Beast is a hybrid – with the head and neck of a serpent, the body of a leopard, the hind of a lion, and the feet of a stag. It name comes from its bark because it sounds like the barking of twenty hounds on the quest. Credit for picture In Sir Thomas Malory's Le Morte d'Arthur, the Questing Beast appears to Arthur after he unknowingly slept with his half-sister, Morgause. Their son, Mordred, eventually kills Arthur. Merlin says that the Questing Beast is the offspring of an incestuous union between a royal brother and sister, like Mordred.