Imagined technological advancements or natural settings which are currently unreal in the present day but could be invented, caused, or explained by science in the future. The narrative of science fiction (Sci-Fi or SF) stories focuses on the societal or individual reprecussions caused by the imagined technology or natural phenomenon, and are frequently dystopian in nature. Sufficient world-building is required for a work to be Sci-Fi; an alien simply visiting from outer space and living on Earth with unusual powers would be Supernatural. Characters in Sci-Fi stories can have unnatural powers without a Fantasy/Supernatural tag, but there should be a plausible scientific reason for these powers described by the creator. A futuristic setting with impossible, unexplained powers (e.g. humans randomly evolved to control the weather via thought) would be Fantasy.