The Troit Boar is a monster with the appearance of a boar but a size beyond even a large horse. Its tusks are as large as a man's forearm; it's saliva is poison; and it can kill a man with one blow.
The beast is said to come from Ireland, where a king was cursed with the form of the beast.
The beast wears like piercings three odd treasures: a comb, a razor and a pair of scissors. These items are said to be the signs of masculinity and very glorious to possess.
Sir Rhodri hunted the beast as part of his attempts to acquire the Cauldron of Dyrnwch the Giant. With his allies he succeeded in knocking the creature unconscious, though Sir Elad, Sir Leo and Sir Dafydd were all seriously injured to the point of near death.
The Troit Boar is from the Welsh tradition of Arthur stories, in particular being the focus of a large part of the story of Culhwch and Olwen.