Spirit Wrack

This spell deals 1d8 points of damage per caster level to any one particular incorporeal undead being such as wraiths, spectres, ghosts, or similar entities within sight of the caster. Alternatively, the caster may choose to cause a burst of 1d4 points of damage per level to any such beings within 20 feet of the caster, whether visible or not. Minor spiritual beings such as poltergeists haunting an area are usually destroyed outright by this spell. Any affected being is allowed a save for half damage. Some persistent types of undead may reform after the passage of some time (typically days later), and may require certain rituals or other requirements be fulfilled before being permanently destroyed. This spell only affects true incorporeal undead and does nothing against other types of beings, even if they happen to be insubstantial at the time; vampires that happen to be in gaseous form are immune to this spell's effect.