BiaGae (cowie shell, commonly filled with mercury and tarkut) is a special kind of amulet which is widely use to avoid and protect from Black Magic, evil forces, ghosts and spirits.  

Bia Gae amulets  are known to be effective for protection and in particular from evil influences and malevolant spirits.It is not uncommon for persons on their death bed to request such an amulet as protection from spirits that will endlessly disturb and torture the dying.The amulets will also help to set the soul free and give protection beyond the grave ,ensuring a smooth passage into the next life.