Related Clues:
- '...under the whelming ___': Milton
- Not from Earth
- Not terrestrial, perhaps
- Sci-fi film extra
- Sweeping force
- Daily riser
- An American in Paris, e.g.
- Not terrestrial
- Threat to a sandcastle
- 'The ___ stayeth for no man': William Camden
- It waits for no man
- Not natural
- Xenophobe's fear
- With 27-Down, sci-fi phenomena that help explain this puzzle's theme
- Current event?