It is, in fact, a fulacht fia, one of Ireland's most widespread and persistently mysterious prehistoric monument types. Fulachtaí fia are the horseshoe-shaped or irregular mounds left behind by ancient burnt mound sites, where stones were repeatedly heated and plunged into water-filled troughs, shattering with the thermal shock and accumulating over time into the characteristic scorched heaps we see today. This particular example measures roughly 22 metres from north to south and stands around 0.8 metres high.

What makes the site in Ballymacphilip particularly interesting is not any single monument but the density of them. Within a radius of about 70 metres, at least four other fulachtaí fia have been recorded. A second example sits approximately 60 metres to the north, and a cluster of three more lies around 70 metres to the north-east. This kind of grouping is not unheard of in Ireland, where fulachtaí fia number in the tens of thousands and are sometimes found in loose concentrations near reliable water sources, but finding five in such close proximity in one corner of a Cork pasture still invites questions. Were they used simultaneously by different groups, or do they represent activity returning to the same general area across generations? The burnt mounds themselves offer no easy answer; they tend to be frustratingly silent on the question of exactly what they were for, with theories ranging from outdoor cooking and food processing to hide preparation, textile work, or even some form of communal bathing.