In Welsh tradition, a boar who had once been a king. The animal carried comb and shears between its ears, objects which were needed by the giant Ysbaddaden so that he could shave for the wedding of his daughter Olwen with the hero Culhwch.
The boar was chased by King Arthur and his knights, accompanied by Mabon mab Modron and Gwyn ap Nudd, all across Ireland, Wales and Cornwall, where it finally jumped into the sea. Luckily, the objects had been retrieved before that time. See also Ysgithyrwyn.