Afrit

Entry in A Dictionary of Ghost Lore
The Arabian Afrit is the spirit of a man who has been murdered and rises to avenge the murder. According to an acient tradition, the afrit emerges from the slain person's blood wherever it falls on the ground, materializing rather like smoke from a fire. The activities of these spirits can be quite terrifying, and the only way to prevent their appearing is to drive a new nail into the ground where the murder was committed. Experts have noted that this tradition--known as "nailing down the ghost"--has a certain simularity with the method prescribed in European folklore for dealing with vampires.