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 laid. It was finally dragged away to the lake Cwm Ffynnon, or killed by Peredur.
Some later legends ascribe the creature's death to King Arthur or to Percival (Peredur's name in the later Arthurian legend of the continent and England). Close to Llyn Barfog in Snowdonia is a hoof-print petrosomatoglyph etched deep into the rock "Carn March Arthur", or the "Stone of Arthur's Horse", which was supposedly made by King Arthur's mount, Llamrai, when it was hauling the afanc from the lake.
According to one version of the myth, also put forth by Iolo Morgannwg, Hu Gadarn's oxen dragged the afanc out of the lake; once it was out of the water, it was powerless and could be killed. This version locates the creature in Llyn Llion.
China Miéville's The Scar features a large afanc (spelled as avanc), bound by chains to tow the city of Armada across the oceans. The afanc in The Scar is of phenomenal size, so vast that to observers one vein on the creature's surface looks like a high ridge.
Stephen Lawhead's Song of Albion series features a brief encounter with an afanc which inhabits a bay of Tir Aflan (the "Foul Land") in the Otherworld. Warriors in two ships are able to kill it with spears, puncturing its hide, and hitting it in the eye and open mouth.
The Afanc plays a leading role in episode three of Merlin - it's a creature made of earth and water which can be destroyed by fire and wind. It poisons Camelot's water supply, causing a supernatural plague.