Superstition such as black cats.
Black cats have played a major role for centuries in folklore, superstition, and mythology. Black cats in the middle ages were believed to be witches' familiars, and some people even believed them to be witches incarnate. Many of these old superstitions about black cats exist to this day. The cat was worshipped in Egypt and to kill one was considered a capital crime. When an Egyptian family's cat died, the cat was mummified and the family went into mourning. Romans, also, considered the cat sacred and introduced it into Europe. http://www.csicop.org/superstition/library/black_cats/