Call of Duty Zombies

Call of Duty has completely changed the gaming world with their zombies mode. Started by Treyarch's Call of Duty: World at War, this game mode was an instant hit. It was originally meant just as an extra surprise after completing the campaign mode. THe mode instantly exploded with fans, resulting in 3 DLCs, each with their own terrifying map to fight endless hordes of the undead on. When playing the game, one player heard a zombie shouting the name,"Sam" while charging after them. They asked Treyarch, who was not aware of the voice clip, what the name meant. Though it wasn't originally meant to stand for amything, the name sparked a storyline of its own. The mode has stretched across three games, all made by Treyarch, and is rumored to be in the new game, Advanced Warfare, which is made by MW3 co-developer Sledgehammer Games. It has even sparked inspiration for entire games, as many fan made indie games have shown up since 2008.

Picture from here.