The Afanc is a gigantic monster that lives in Llyn-yr-Afanc (The Afanc Pool) in the River Conwy.
He's so strong that when he's in a bad mood, he breaks the banks of the pool, causing floods that bring disaster to the people of the Vale of Conwy. Crops are ruined, cattle are drowned and houses swamped with water.
Something must be done to stop the Afanc but he seems to be indestructible. The young men of the Vale attack the beast with every weapon available to them - spears, arrows and swords - but no man-made weapon can harm him.
Read the rest of the article... I loves me some sea monsters (or in this case river monsters)...