Rhadamanthus
From Tardis Wiki, the free Doctor Who reference
Rhadamanthus was one of the fey folk. Banished from his world, he became a cat, Olive Hawthorne's familiar, only able to visit home once every seven years. Each time he did he returned as a new cat. (HOMEVID: The Cat Who Walks Through Worlds, PROSE: The Cat Who Walks Through Worlds)
