The ustrel was a blood thirsty vampire of Bulgaria. The ustrel was not something that most people could actually see. It was described as the spirit of a child who had been born on a Saturday but died before receiving a baptism.
On the ninth day after its burial, the ustrel was thought to work its way out of the grave and attack cattle or sheep by draining their blood. After feasting all night, it would return to its grave before dawn. After about 10 days of feeding, the ustrel was thought to be strong enough that it did not need to return to its grave; instead, it would find a resting place during the day, either between the horns of a calf or ram, or between the hind legs of a milch-cow. The ustrel would pick out a large herd and would begin to work its way, eating the fattest animal first. The animals that it attacked would die the same night. If the dead animal was cut open the next day, the signs of the wound the vampire made would then be evident.
Generally, one knew that it had and ustrel in its herd when there were several unexplained deaths of sheep and cow.
If a ustrel was thought to be around, the owner of the herd could hire a vampirdzhija, or vampire hunter, which was a special person who had the ability to see them. Once detected, the village would go through a particular ritual known throughout Europe as the lighting of a need-fire.
Beginning on a Saturday morning, all the fires in the village were put out. The cattle and sheep were gathered in an open space, and then were marched to a nearby crossroads where two bonfires were set. The bonfires were lit by a new fire created by rubbing sticks together, and the herd would be guided between the fires.
Those who performed this ritual believed that the vampire dropped from the animal on who body it had made home and remained at the crossroads where wolves would devour it.
Before the bonfires burned out, someone would take a flame into the village and use it to rekindle all the household fires.