In most of Europe a black cat arriving at one’s home is actually considered good luck. Somewhere along the line as the separatists fled to America for religious freedom, they became associated with evil and witchcraft. Many early settlers believed that witches could take the form of black cats in order to sneak around in the darkness and wreak havoc.
The association with witchcraft is also how the myth that cats have nine lives began. It was rumoured that a witch had the ability to shape-shift into a cat nine times.