Alien in the paranormal sense refers to any extraterrestrial being, particularly those who come to Earth and interact with humans in some way. Reports of alien encounters typically involve the presence of a UFO.
Though the discovery of alien life has yet to be scientifically accredited, there are a few alien races that are purported to have been identified by believers in alien phenomena.
Reports of alien abduction are a common theme where aliens meet popular culture. Critics have speculated that alien abduction reports are actually misinterpreted hypnagogic events (essentially hallucinating while half asleep), especially during sleep paralysis.