Undead describes creatures in stories and games that are dead but still moving around. A zombie is undead because its body keeps walking even though it's no longer alive. A vampire is undead because it died as a human but continues to exist in a strange, immortal state. Skeletons that rattle around in fantasy stories are undead too.

The word captures something that doesn't fit into normal categories: not alive, but not resting peacefully either. These creatures occupy an unsettling middle ground. In video games like Minecraft, players fight undead mobs like zombies and skeletons. In books and movies, undead creatures often serve as villains or monsters that heroes must defeat.

The word works as both an adjective (an undead warrior) and a noun (fighting the undead). Writers use undead creatures to explore creepy “what if” questions: What if death wasn't the end? What if something could keep moving without being truly alive? While undead creatures are fictional, they've become a standard part of fantasy and horror storytelling, appearing everywhere from ancient legends to modern games.