The structure sits roughly 425 metres east-southeast of the early medieval ecclesiastical site associated with St Colman Mac Duagh, and its identity has been fixed in local memory long enough to appear on the 1915 edition of the Ordnance Survey six-inch map, labelled plainly as the grave of St MacDuagh's servant.

The legend, recorded by the antiquarian T. J. Westropp in the early twentieth century, reaches back to around AD 630. St Colman Mac Duagh and his servant had been living an ascetic existence, surviving on the most meagre of rations, when a miraculous feast sent by King Guaire of Connacht arrived to sustain them. The servant, overwhelmed after such prolonged deprivation, ate far beyond what his body could bear and died of overindulgence. It is a story that sits at an odd angle to conventional hagiography, less a tale of martyrdom or miraculous healing than a cautionary footnote to saintly endurance. The structure itself is a subrectangular mound enclosing a small rectangular fissure cut into the natural bedrock, about 2.55 metres east to west and just over a metre wide, roofed by two large thin flagstones laid one atop the other and opening to the north. A short curved passage, partly defined by natural rock outcrop and partly by a collapsed drystone wall, leads to the opening. Two penitential cairns, small mounds of stones associated with acts of prayer or penance, stand about two metres to the west, joined by a wall, suggesting the site continued to function as a place of some devotional significance well beyond its founding legend. Archaeologists have noted it cautiously as a possible megalithic structure, though its relationship to natural fissures in the Burren limestone complicates any straightforward classification.