Silvia

“You see, a witch has to have a familiar, some little animal like a cat or a toad. He helps her somehow. When the witch dies the familiar is suppose to die too, but sometimes it doesn't. Sometimes, if it's absorbed enough magic, it lives on. Maybe this toad found its way south from Salem, from the days when Cotton Mather was hanging witches. Or maybe Lafitte had a Creole girl who called on the Black Man in the pirate-haven of Barataria. The Gulf is full of ghosts and memories, and one of those ghosts might very well be that of a woman with warlock blood who'd come from Europe a long time ago, and died on the new continent.

And possibly her familiar didn't know the way home. There's not much room for magic in America now, but once there was room.

("Before I Wake...")”
― Henry Kuttner, Masters of Horror