This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Barghest (England)
In Northern English folklore, the Barghest or Barguest is a mythical monstrous black dog with large teeth and claws, though in other cases the name can refer to a ghost or household elf, especially in Northumberland and Durham, such as the Cauld Lad of Hylton. The Barghest often serves as an omen of death. At the passing of a notable person the Barghest may appear, followed by all the other dogs of the local area in a kind of funeral procession, heralding the person's death with howling and barking.
If anyone were to get in the Barghest's way it would strike out with its paw and leave a wound that never heals.Besides taking the form of a large black dog with fiery eyes, it may also become invisible and walk about with the sound of rattling chains. It may also foretell the death of an individual by laying across the threshold of his or her house, and like the vampire the Barghest is unable to cross rivers.