Further north along the shores of Lough Derg, near the village of Terryglass, stands the site of Castle Biggs—a location long associated with darker strands of local folklore. Unlike many Irish hauntings tied to former residents or tragic events, the tales surrounding Castle Biggs speak of something far more unsettling: a Shuck, a supernatural black dog rooted in British and Irish folkloric tradition.

This creature is described not merely as a spectral hound, but as a demonic guardian, often depicted with glowing eyes and cloven hooves—a detail that sets it apart from the typical phantom dogs of legend. According to local lore, this monstrous apparition patrols the ruins to protect a hidden hoard of treasure buried somewhere on the old castle grounds.

Those who claim to have encountered the Shuck describe an overwhelming sense of dread, as if the creature is warning intruders away from something long concealed beneath the earth.