The Adventure of the Sussex Vampire
Here is an interesting piece of information I got on Wikipedia regarding the Adventure of the Sussex Vampire on an aside Sherlock Holmes makes to Dr Watson.
"Matilda Briggs was not the name of a young woman, Watson, ... It was a ship which is associated with the giant rat of Sumatra, a story for which the world is not yet prepared."
How the ship, the mammal, and the Indonesian island are associated is not specified. Rats commonly colonize ships, and so there is an obvious line of speculation.
Another train of thought follows the reasoning that Matilda Briggs actually was the name of a young woman as well as a fictional ship—for the famous "mystery ship," the Mary Celeste, which was found abandoned at sea in 1872, had sailed under the command of Captain Benjamin Briggs, whose daughter, Sophia Matilda Briggs, was a passenger on the doomed merchant brigantine.
Doyle was certainly familiar with the Briggs family, for in the January 1884 issue of the Cornhill Magazine, when he was but a 25-year-old ship's surgeon, he had published a short story about the mysteriously abandoned Mary Celeste titled "J. Habakuk Jephson's Statement".
As it was a work of fiction, Doyle did not adhere strictly to the facts; he renamed the ship Marie Celeste, the captain's name was given as "J.W. Tibbs", and the fatal voyage was said to have taken place in 1873—but his story proved so popular and influential that many people to this day still refer to the vessel as the Marie, rather than the Mary Celeste.