A Planet-Killer is a fictional "doomsday device" prominent in the genre of science-fiction: a Planet-Killer is a vessel or other mechanism with the power to either destroy a planet entirely or damage it to the extent it can no longer sustain life as we know it. The most famous example of a Planet-Killer in popular fiction is, of course, the Death Star from Star Wars but a number of other planet-killers exist in science-fiction media ranging from films, books and video-games.