The term "undead" refers to beings that are neither fully alive nor completely dead. This concept often includes creatures like zombies, vampires, and ghosts, which are typically depicted in folklore, literature, and popular media. Undead entities often exhibit characteristics of both life and death, such as movement or consciousness, but may lack the vitality associated with living beings. In many stories, the undead are portrayed as having a desire for human flesh or blood, or they may seek revenge for their untimely demise. They often serve as symbols of fear, loss, or the consequences of tampering with life and death, making them a popular subject in horror genres.