The vyrkolakas is a vampiric spirit from Greek lore (see GREEK VAMPIRES). When a werewolf dies, its spirit will return and possess a corpse, which it will animate in order to use as its own. Since the spirit is an entity apart from the body it occupies, it is not considered a REVENANT. Once the body becomes possessed, timpanios will occur, meaning its bloated body will become hard, and the skin will become so tight that when it is slapped it will sound like a drum. There is at least one vyrkolakas in every Greek clan. The vyrkolakas will walk through the community it used to live in, spreading disease and calling out the names of people it once knew. Anyone who happens to see it and look directly at it will die instantly; anyone who should answer its call will die within 24 hours.

Source: Guiley, Complete Vampire Companion, 26; Senn, Were-wolf and Vampire in Romania, 64; Summers, Vampire in Lore and Legend, 258