1827: ’Bargest’ Reports from Grassington
In 1827, William Hone published two odd accounts about a spectral animal called a Bargest believed to exist in and about the town of Grassington in North Yorkshire, England. While Hone and later authors equated this beast with spectre-hounds and Black Dogs, this identification of the beast may be debatible, in that the creature as described is something of a shapeshifter, and seems to favor large bear-like forms over that of dogs.
What's not debatible is that one of Hone's tales of a Bargest is very likely the first description of a phantom animal with "saucer-like" eyes. In addition, Hone stated that "the appearance of the spectre hound is said to precede a death," which is the earliest statement I've found of this belief so far, though modern encounter reports appear to strongly disprove this thought.