A canine was once the companion animal of the farmboy Luke Skywalker prior to his departure from his home planet of Tatooine on the Millennium Falcon in 0 BBY. As the vessel initiated hyperspace for its journey to the planet Alderaan, Skywalker was contemplating the dog.
The initial reference to Luke Skywalker's dog appeared within the novelization of Star Wars: Episode IV A New Hope, which was released in 1976 and authored by Alan Dean Foster. It represents one of multiple instances where animals from the real world are referenced within the novel.