alien or little green man which is an extra-terrestrial creature often used as a halloween subject

alien green extraterrestrial creature roswell ufo unidentified flying object uap space spaceship life intergalactic outer otherworldly visitor phenomenon cosmic inhabitant unearthly interstellar species celestial little man generative eyes halloween isolated cut white background horror monster abduction close encounter third kind contact ariel crop circles travel science fiction humanoid person head poster extra-terrestrial used subject computer