Related Clues:
- Acting ambassador?
- Not terrestrial, perhaps
- Strengthened
- Sci-fi film extra
- See 41-Across
- Disobeyed a zoo sign?
- An American in Paris, e.g.
- Not terrestrial
- Gave, as lines
- Middleman
- Not natural
- Hoover employee, once
- Xenophobe's fear
- With 27-Down, sci-fi phenomena that help explain this puzzle's theme
- Maxwell Smart, for one