"Merely a symbol of your own self-doubt," Narcissa replied, dismissively. "An animal safe and unassuming. But you have been blessed by Lily Potter now ... and can you guess what her Patronus was? In any case, you are an intelligent witch ... you should be aware that a Patronus can change, or even be chosen. But even with a Patronus as an otter ... that is not too far away from a certain surname I know you covet. It was another pointer for you, to the direction you needed to go."