Zombies are fictional undead creatures. It is believed that zombies are corpses of animals/humans that have "reanimated" themselves to walk the Earth again. Zombies are depicted as having green skin, with features such as their eyes and most part of their skin missing. It is also assumed that the infectious bite from a zombie causes the target to slowly mutate into a zombie as well. There are a multitude of theories about the possibility of a "Zombie Apocalypse".
In Video Games
Zombies have been appearing in video games for decades. The first known use of zombies in a video game comes from the 1984 ZX Spectrum game Zombie Zombie. Since then, zombies have become more and more detailed, some learning how to use weapons, break off nailed boards, and even regenerate body parts. The Call of Duty series has it's own game mode called "Nazi Zombies" which focuses on a single person (or a group, up to 4 (or 8))) attempting to survive an unlimited amount of zombies, each level becoming increasingly difficult. Some MMORPGs, such as EverQuest and World of Warcraft feature zombies as common enemies.