Striga (Polish pronunciation: [‘stʂɨɡa]) a female demon or Strigon – male equivalent is derived from an old slavonic folk demonology. The name of this demon comes from roman “strix” which means an owl, because the former slavics believed that a man became a Striga when he got back from the deads world as a woman with bird claws, so she can feed herself with children’s blood-this is why Striga is qualified as a vampiric demon. This way, Striga was taking a revenge for harm, that she experienced as a human, and also for no worthy burial. The second one had it’s source in fear which included people, who noticed, that their child was possibly born with features, that could turn him into a Striga.
Striga was born as a child with two souls, two hearts and a double row of teeth (the second row was barely visible, it grew accordingly with a child’s growth). Such children weren’t born accidentally, usually it happened due to a curse that was thrown on a pregnant mother, or the fetus was transformed by the devil. If a newborn was born with grown teeth, he was immediately considered as a Striga and drove out of human seat. However, if the fetus was born dead and wasn’t burried with it’s face down to the bottom (which could prevent becoming a Striga), then it’s second soul and heart still functioned. Right after developing sufficiently all the motor skills of “this child”, Striga began feeding on nearby villages and highways. Though Striga prefered human blood, she was able to survive short term of time by feeding herself with animal blood.
This demon was characterized by an unproportionally large head relative to the body, red eyes, sharp fangs and claws similar to bird’s. Strigas were incredibly fast and agile. Despite their small and inconspicuous measurments, they were also very strong, they could easily knock an adult man or a cow down. Though Striga had superhuman skills, she could be killed in few traditional or invented ways. According to those traditional ways, the most popular was to burn a Striga’s body, while she slept deeply, or to stick a pin to specific parts of her body. Legends preach that a method to break a spell (or to kill her in the last resort) is to spend a night in her crypt and sleep with a face down to the ground. The task was so difficult, because Strigas were especially active during the night and they spent the days in their dens.
You can read about a meeting with a Striga in stories about a Witcher, written by Andrzej Sapkowski, entitled “Ostatnie życzenie”(eng:”the last wish”), where Geralt breaks a spell for a princess, by spending a night in her tomb.