Afanc

The Afanc (Welsh pronunciation: [ˈavank], sometimes also called Addanc, [ˈaðank]) is a lake monster from Welsh mythology. Its exact description varies; it is described variously as resembling a crocodile, beaver or dwarf-like creature, and is sometimes said to be a demon. The lake in which it dwells also varies; it is variously said to live in Llyn Llion, Llyn Barfog, near Brynberian Bridge or in Llyn yr Afanc, a lake near Betws-y-Coed that was named after the creature.

The afanc was a monstrous creature that, like most lake monsters, was said to prey upon any foolish enough to fall into or swim in its lake.

One of the earliest descriptions of it is given by the 15th-century poet Lewys Glyn Cothi, who described it as living in Llyn Syfaddon, now Llangorse Lake in Powys.

One tale relates that it was rendered helpless by a maiden who let it sleep upon her lap; while it slept, the maiden's fellow villagers bound the creature in chains. The creature was awakened and made furious; its enraged thrashings crushed the maiden, in whose lap it still lay. It was finally dragged away to the lake Cwm Ffynnon, or killed by Peredur (Percival, Peredur's name in Chrétien de Troyes' telling of the Arthurian cycle).

In the tale, Peredur son of Efrawg, translated by Lady Charlotte Guest in the Mabinogion taken from the White Book of Rhydderch and Red Book of Hergest, the "Addanc of the Lake" resides in a cave near the "Palace of the Sons of the King of the Tortures". The palace is so named because the Addanc slays the three sons (chieftains) of the king each day, only for them to be resurrected by the maidens of the court. It is not stated why this cycle of violence continues, but when Peredur asks to ride with the three chieftains, who seek out the Addanc daily, they state that they will not accept his company as if he was slain they would not be able to bring him back to life.

...
Wikipedia