THE GWYLLGI, OR DOG OF DARKNESS.
The Gwyllgi was a frightful apparition of a mastiff with baleful breath and blazing red eyes. In former times, an apparition in this shape haunted Pant y Madog, in the neighbourhood of Laugharne, Carmarthenshire. A woman named Rebecca Adams, passing this spot late one night, fell down in a swoon, when she saw the spectral dog coming towards her. When within a few yards of her it stopped, squatted on its hounchers, “and set up such a scream, so loud, so horrible, and so strong, that she thought the earth moved under her.” I was informed at Llangynog five years ago, that Spectral Dogs still haunt that part of Carmarthenshire; and more than one of my informants had seen such apparitions themselves.
A spirit in animal form was not always a demon; sometimes the Spirit of a mortal was doomed to wear this shape for some offence.
It was once believed that the Evil One, either from lust, or from nefarious designs, assumed the form of a young man or a young woman.
The following two stories, the first from South Pembrokeshire, and the other from Gower, have reference to this belief.