Gantz is a dark sci-fi manga and anime about a group of people who die and are inexplicably transported to a sealed room with a mysterious black sphere named Gantz. The sphere forces them to hunt and kill grotesque alien monsters in real-world Japan, using advanced weapons and suits. Players earn points based on their kills, with a chance to be resurrected or freed after reaching a certain score. Readers enjoy it for its extreme violence, moral ambiguity, constant tension, and unpredictable plot twists, as well as its exploration of human nature under life-or-death pressure and the mystery of who or what controls Gantz.