The term SCI-FI KILLER is a combination of two words, 'sci-fi' and 'killer'. Sci-fi is short for science fiction, a genre of literature and film that often involves futuristic settings, advanced technology, and otherworldly elements. A killer is someone who commits murder or other violent acts. Therefore, the term SCI-FI KILLER refers to a person who commits murder or other violent acts in a science fiction setting. The crossword solution for this term is RAY, which could refer to a RAY gun, a type of weapon commonly featured in science fiction stories.