Strzyga
Strzyga, this word is derived from Latinian Strix, which means owl or from Romanian Strigoi which means troubled soul of the dead rising from the grave.To become this horrible it's nessecery to be cursed. Strzyga is kind of vampire with two hearts, two souls and two sets of teeth. A newborn child with already developed teeth was also believed to be one. According to belief, only one of their two souls would pass to the afterlife, other soul resurrected deadman who's killing people. Strzyga was flying in the form of the owl and attacked night-time travelers and people who had wandered off into the woods at night. Stryga was sucking all blood from dead body and was eating internal organs. According to "Witcher" to make Strzyga again a man, it's nessecery to spend night in his tomb.