Name of a lake monster from Welsh mythology that
King *Arthur (or Percival) was later ascribed to have killed. It is variously described as a demon, a dwarf, beaver, or crocodile. It was said to prey upon anyone foolish enough to swim in its lake. The location of the lake in which it dwells also varies: Llyn Barfog, Llyn Llion, Llyn yr Afanc.