A Month of Tom: Day Eighteen

Perhaps the most popular, enduring companion of all time, I present K-9! I have to admit, I wasn't very fond of him in the beginning. I mean, really, he's a robot dog. It wasn't until I saw him interacting with Leela that I really fell for him, and then the love sort of went retroactive. And, even though I'm a cat-person myself, there's definitely something to be said about a man and his dog. So I here you go, the Doctor and his dog.