Well, technically not a real vampire.  It was a guy who was stoned on some really good stuff and THOUGHT he was a vampire.   Story comes out of the Lacrosse Tribune where it's reported the man punched a guitarist for the band American Fang who were playing in La Crosse that night.

The man then reportedly drove a barricade through a window of the tour bus, claiming other vampire attacks were imminent from members of Hollywood Undead, who the man also accused of being Vampires and attacking him.

Funny, I always thought of Vampires as being pretty non-violent in nature.  Perhaps this is a new breed of Vampire that forgoes all the seductive neck biting blood sucking techniques for a little MMA like action that I'm unaware of.