Whether caused by a diease, vodoo, or an act of god, the transformation of the zombie is one of the more unique aspects of this particular monster, especially compared against the transformations the Vampire and the Werewolf undergo. For, unlike the vampire, the transformation of a zombie is not a scene in which the monster reveals its true nature. Neither is it a temporary transformation like that of the werewolf. Instead its transformation is more along the lines of a transition: a transition from being human to being a monster. When this transformation happens, it is almost always permanent. Once a person turns into a zombie, there is no going back. In contrast there are more stories in which vampirism and Lycanthropy can be cured through pretty reasonable means such as killing the vampire or werewolf that infected you. Such a procedure is never an option when talking about zombies. Even when a cure is possible, it usually only comes about as the result of expensive medical research or meeting equally difficult and complex magical conditions.
Even in stories where a cure for zombies is available, there is still a time restriction and shortage that says who can and cannot be saved. And even then, those infected usually cannot be saved once they have fully gone through the transformation process into a zombie or have only recently transformed. This makes the transformation process into a zombie all the more painful for the audience once a human character is infected. For once they are infected it's only a matter of time before they turn. It is an inevitability that leads to tear-jerking last words, desparate last stands, or, even worse, one character being forced to mercy kill another to prevent the infected from turning on them. A brillant depiction of this occurs in the Telltale Game The Walking Dead: Episode 5 . At the end of this episode, the player's main character, Lee, has been taking care of a little girl named Clementine in the midst of the Zombie Apocalypse. Through the course of previous installments of the game, Lee becomes infected and, at the end of Episode 5, is beginning to succumb to the infection. Knowing he may very well turn on Clementine, Lee instructs her to handcuff him to a radiator and shoot him to ensure he doesn't turn (See below).
It is in this emotional turmoil that the transformation sequence holds the most weight and contributes the most to a zombie's fear factor. Yes, the zombie isn't the most versatile, skilled, or powerful monster there is, but all it takes is one moment of bad luck or the wrong decision to make you join their ranks. To make matters worse, the more zombies there are, the potential for mistakes or bad calls rises until you completly run out of luck and become one of them.
