Cath Palug
Cath Palug (also Cath Paluc, Cath Balug, Cath Balwg, literally 'Palug's Cat') was a monstrous cat in Welsh mythology associated with Arthurian legend. Given birth to in Gwynedd by the pig Henwen of Cornwall, the cat was to haunt the Isle of Anglesey until Kay went to the island to hunt it down.