My favorite mythical creature and/or character would have to be the sirens from Greek mythology, most notably found in Homer's Odyssey. I think the reason I enjoy them so much is because they use their alluring voices to draw in their prey. Considering my rather obsessive love for music, this isn't really surprising if you can look past the fact that I read vampire stories (good ones where they're monsters out to drain the blood from our veins and not just be pathetic glittery idiots). I've had many friends who couldn't seem to wrap their mind around that fact but whatevs.
Sirens, while representing another moment in history where women are horrid creatures designed to lead men into ruin (as if the morons need more coddling), also represent a little bit of that vindictive mindset behind the hunger for weak-willed men's flesh that makes me smile all creepy-like :D Honestly, if that's what they need to do to eat and survive, it just sucks to be a sailor!