Doctor Who's Bad Wolf.

What's going on in the new Doctor Who? I've become a huge fan of the new series, which is surprising, as I never really got hooked into the original.

Scott Matthewman has noticed a consistant pattern of Bad Wolf (and maybe other faerie tale) references throughout the series. There are obvious spoilers in the first link, as well as in the follow up post he made that details last Saturday's episode. It's been announced that the title of the last episode will indeed be "Bad Wolf", so it's all leading up to a significant ending, but what, or whom, is Bad Wolf?

I so can't wait.