Barghest n. : A goblin, in the shape of a large dog, portending misfortune.

Example:
Does anyone know a good evil sounding name that is unisex?

Taxonomy
Barghest, black dog, dog, free encyclopedia, Barguest, legend, geist, goblin, north of England, folklore, ghost, spectre, Darlington, derivation, bier, The Whitby Witches, beast, birds.

Defination from the web:
Barghest, Bargtjest, Bo-guest, Bargest or Barguest is the name often given in the north of England, especially in Yorkshire, to a legendary ... There is also a story of a Barghest entering the city of York occasionally, where, according to legend, it preys on lone travellers in the city's ...