Questing Beast

A monstrous creature in Arthurian legend, with a body that is part serpent, part deer, and part leopard. Although it has four legs, the sound of thirty hooves was heard whenever it ran. The beast was relentlessly pursued by either Pellinore or Palomides. The Questing Beast was, in fact, a human boy who was transformed into an animal by the horror of seeing his mother torn apart by wild dogs.

The animal appears in the Prose Tristan, Perlesvaus, the Post-Vulgate cycle, and in Malory's Le Morte d'Arthur.