When i was walking through Devil's pass this thing went into my mind. Zombie horde event. I mean event like an airdrop or radiation. Horde will appear somewhere in the forest so it does not cause lag in the cities plus there will be no way to cheat it by walking on a car etc. Zombies from the horde will have diffrent drops maybe even more exp but they will be harder. Maybe not double health like in radiation event but i'm thinking about maybe more damage more to chance to get infected or maybe more speed of the group.