Reducing a vampire's hit points to 0 or lower incapacitates it but doesn't always destroy it (see fast healing). However, certain attacks can slay vampires. Exposing any vampire to direct sunlight staggers it on the first round of exposure and destroys it utterly on the second consecutive round of exposure if it does not escape. Each round of immersion in running water inflicts damage on a vampire equal to one-third of its maximum hit points-a vampire reduced to 0 hit points in this manner is destroyed. Driving a wooden stake through a helpless vampire's heart instantly slays it (this is a full-round action). However, it returns to life if the stake is removed, unless the head is also severed and anointed with holy water.