What's your favorite fantasy creature?

I usually like unicorns or werewolves. I got into werewolves during Harry Potter, and this new show on the Sci Fi channel called "Sanctuary" has a really cool werewolf named Henry. I've liked unicorns since I was a kid. I'm also somewhat partial to mermaids, although I wonder where the guys of the species are. You never really see mermen. Perhaps I could write a story about a merman, and why there are so few of them.