The upor is a Russian vampiric REVENANT that preys on the blood of children. In addition to its ability to shape-shift into chickens, dogs, insects, rats, and small birds, it can also create an empathic and telepathic link with numerous types of animals. Once the empathic link has been established, the upor can use the animal as its familiar as well as use it to spy on potential victims. To destroy an upor, its grave must first be found, and then a successful exorcism must be performed on the corpse.

Source: Indiana University, Journal, vol.14, 255; Maberry, Vampire Universe, 285; Perkowski, The Darkling, 115

From Polish vampire lore, the upioras is described as looking like a large man. It attacks its victims at night by grabbing them up and smashing their bodies around until their bones are completely pulped. It then sucks out the soup it has made. When it has finished eating, it skins the corpses and wears the skins of its victims. To destroy an upioras, it must be completely soaked in holy water.

Source: Georgieva, Bulgarian Mythology; Perkowski, The Darkling, 166

The Ruthenian people of eastern Poland have in their lore a vampiric REVENANT called an upierzyca. Always described as a beautiful young woman, on nights of the full moon, the upierzyca hunts for young men. It attacks them and, using the barb on the end of its tongue, will pierce their skin, draining them of their blood.

If a deceased woman is suspected of being an upierzyca, her body must be exhumed. Upon examination the body will not only be undecayed, but the creature’s eyes, head, and mouth will still be moving. Its burial shroud may also shows signs of having been partially consumed.

Source: Dundes, Vampire Casebook, 8; Haining, Dictionary of Vampires, 254; Masters, Natural History of the Vampire, 101; Perkowski, The Darkling, 113; Volta, The Vampire, 143