In Albania there is a particularly vicious type of vampiric REVENANT known as a wurwolaka. It is one of the few vampires that has the ability to create more of its own kind. The wurwolaka is an ambush predator, and at night it attacks humans, ripping them apart and drinking their blood. Anyone who looks upon it will be stricken with insanity. The only way to destroy this vampire is to burn its body to ashes.

Source: Aylesworth, The Story of Vampires, 5; Wright, The Book of Vampires 105