Also known as Addanc, it is a lake monster from Welsh lore. Both the lake and it's appearance has varied: it has been described as resembling a crocodile, beaver, dwarf-like, and is sometimes said to be a demon. Meanwhile, the lakes it live in are said to be Llyn Llion, Llyn Barfog, near Brynberian Bridge, and in Llyn yr Afanc. The Afanc would prey upon anyone foolish enough to fall into or swim in its lake.
"A lake monster that looks like a giant beaver, said to dwell in stagnant rivers. It causes whirlpools and drags down those who look into them. Its strength is monstrous, greater than many men together, but it is weak in the face of a maiden. There is a tale where one was lured onto land and ended up captured by the powers of a bull."