'World War Z' Behind the Scenes Video Shows Zombies Run Amok (Video)

Extras are attacked by the undead as filming on the Brad Pitt-starring film continues in Glasgow.

A pair of fan-shot videos from the Glasgow set of Brad Pitt's upcoming zombie epic World War Z have surfaced online.

The Scottish city is standing in for Philadelphia in this film directed by Marc Forster, and also starring Matthew Fox, Bryan Cranston and Mireille Enos.

STORY: 'World War Z': Brad Pitt to Begin Filming in Glasgow

The videos depict mass panic in the streets of the city as zombies run amok, pushing people from cars and biting. Though the appearance of the zombies isn't surprising -- they look like people, after all -- what is surprising is how quickly the zombie bites transform their victims. In the first video, an unfortunate commuter escapes from his car, gets chomped on and almost immediately begins to spasm and throw himself against the side of his car. Only when the filming stops does he return to normal.

In the second video, we can see what happens just off camera during a mass crowd scene, with crew members urging on the stampeding extras.

The film is scheduled to be released in December 2012.