Desiccation is a state of extreme dryness or dehydration. It is a weakness possessed by Vampires, who depend on the blood of the living to sustain themselves. When Vampires do not feed on blood, their bodies will grow increasingly weak and will eventually dehydrate completely, resulting a state resembling mummification.
Desiccation will not kill Vampires, but leave them trapped inside a mummified body as little more than a corpse, unable to move or recover unless they are fed blood.