What is "vrykolakas"

n. a harmful undead creature (vampire) in Greek folklore

The vrykolakas ( Greek βρυκόλακας, pronounced ), variant vorvolakas or vourdoulakas, is a harmful undead creature in Greek folklore. It has similarities to many different legendary creatures, but is generally equated with the vampire of the folklore of the neighbouring Slavic countries. While the two are very similar, blood-drinking is only marginally associated with the vrykolakas.