Well as everyone is aware by now, I'm sure, the Dawnguard quest begins when vampires are attacking towns at night. Well, there was an attack on Whiterun, but it wasn't vampires... I saw a Cave Bear, a necromancer, a Draugr, a Bandit, some Foresworn, and a Thalmor Wizard to top it off.

... What just happened?

I had this weird bug about a month before Dawnguard was released. I'd fast travel back to a town and it seems like I had "friends" come with me, and there would spawn Draugr, Bears and Bandits etc. It's happened when I travel to Whiterun, the College and Markarth. :S

Once three Draugrs attacked a village..