The Barrier Spells are supernatural spells which appear as Latin phrases and they featured in the 2001 supernatural horror movie Thirteen Ghosts (also known as Thir13en Ghosts). Spirits (or ghosts as one call them) cannot cross barrier spells, as they must obey whatever a spell says because as explained by psychic Dennis Rafkin that the spiritual universe has it's own set of laws compared to the natural world. The walls of the Basileus Machine as well as it's panes of Ectobar Glass had Barrier Spells etched onto them to prevent the ghosts needed to power the eldritch machinery from escaping.