Code Lyoko

When Xana possesses Kiwi, it turns the little dog into the carrier for a virulent virus that turns those it infects into zombies. To make matters worse, Aelita and Jeremie are stuck in the cafeteria and can't get to the factory. On top of that, Odd is a zombie himself. Jermie and Aelita escape but Ulrich and the other students (except William, who is turned into one himself) fight the rest.