In legend, a familiar or familiar spirit is a supernatural being that helps and supports a witch or magician. Traditionally, a familiar is an animal, but some are said to be humanoid. Familiars often have special powers of their own. A Familiar can be a spirit accessed on the spiritual plain as well as a real animal in your household.
The stereotypical familiar in Western culture is the black cat. Because black cats are strongly associated with witchcraft, there are a number of superstitions regarding them. A black cat crossing ones path is said to be a portent of doom, for example. A familiar may be nearly any animal, however. Other common forms for a familiar to take are a dog, an owl, and a toad.