At the outer edge of a fosse, the defensive ditch surrounding an early medieval enclosure in Killerguile, County Waterford, sits a large worked stone that has quietly outlasted most of what once stood around it. It is a bullaun stone, a type of boulder or slab into which one or more cup-shaped basins have been deliberately ground, most likely by human hand over a long period. Bullauns are found across Ireland, often near early ecclesiastical sites, and their original purpose remains genuinely uncertain; theories range from the practical, grinding grain or preparing pigments, to the ritual, with water collecting in the basins sometimes considered to have curative or votive significance. This particular example measures roughly 1.2 metres in length and carries a single basin about 40 centimetres across and 20 centimetres deep.

What gives the Killerguile stone a quietly complicated history is that it does not appear to have always occupied its current position. Writing in his 1952 study of the placenames of the Decies, the historical region of west Waterford, P. Power noted that the stone had at some earlier point been located somewhere near the eastern boundary of the townland, though precisely where was already lost to memory by the time he recorded it. Its migration to the edge of the enclosure fosse, whether deliberate or incidental, means the stone now sits in a layered archaeological landscape, associated with a feature that predates any written record of the area, yet carrying its own separate and partially forgotten trajectory.