A fetch is a mysterious phenomenon which frequently appears in Irish and British folklore. A fetch can be a spirit, double, or an apparition. Sometimes it is referred to as a wraith. It can be an apparition or vision of the person of whom it is supposed to presage death in almost every detail but appears as a ghostly, shadowy figure.
It may be seen by more than one person at a time, and may even be seen by the person which it represents. Belief has it that if the fetch is seen in the morning, its original is expected to enjoy a long life; but, if the fetch is seen at night, then a speedy death awaits the person.
Originally fetches appeared in folklore, but modern sophisticated writers are increasingly beginning to use them in stories because it is very gruesome for a person to be spoke by his double. A.G.H.