This spell was centered on a vial containing a specially prepared liquid. When cast, the spell activated the liquid within the vial, which was then thrown towards a target. The vial shattered, covering a targeted creature in the liquid. As a result, parts of the creature's body began to rot. The vial had to be used within two hours after being exposed to sunlight but could be stored long-term in a dark location. If the vial was opened, the liquid within rapidly lost its power, becoming useless.
In addition to verbal and somatic components, the spell required a material component: the vial and the liquid within. The liquid was brewed by the caster beforehand. It was made by boiling the remains of either a ghast or a ghost, rendering them for a full 24 hours. Other ingredients were mixed in during the process. The caster was then able to fill about six small vials.