Rovio is joining in the annual glut of Halloween-themed updates, with zombie pigs appearing in both Bad Piggies and the Facebook and mobile game Angry Birds Friends. The zombie pigs already hit Bad Piggies on October 17, with the "Tusk til Dawn" update adding 30 new stages.

The undead pigs will also make an appearance in an Angry Birds Friends tournament, to begin tomorrow. The update will bring custom slingshots that can be purchased for each bird to mow down the zombie hordes. A trailer (below) has Rovio's spin on the classic Vincent Price narration from Michael Jackson's Thriller.

Other Halloween-themed goodies for Angry Birds fans include an episode of Angry Birds Toons titled "Night of the Living Pork," and printable zombie mask on the official site.