The Afanc can only be defeated with magic, specifically the use of the oppositional base elements of Fire and Air. The Afanc is said to be a beast born of clay and conjured only by the most powerful sorcerers. In fact, Nimueh shaped a piece of clay into the figure of a small animal while chanting a spell ("Ic acennan eowic ac ic hredde eowic"). She put in into an egg shaped box with markings on it, including her mark, then dropped it into a pool of water leading it to Camelot's water source.