- Extraterrestrials contact humanity but only appear to be friendly:
- Examples:
- "To Serve Man" episode of The Twilight Zone 1962
- Human species degenerates through speciation:
Examples:
- Poul Anderson's "Ghetto," a short story in William F. Nolan's collection A Wilderness of Stars and "The Horn of Time the Hunter," a short story in his collection The Horn of Time
- Overpopulation forces humans to live in immense towers or beneath the ground:
- Examples:
- Towers: Mack Reynolds' novel The Towers of Utopia
- Astronaut trapped in an airlock:
- Examples
- 2001: A Space Odyssey 1968 film
- Post-Apocalyptic Barbarism
- Examples
- A Boy and His Dog 1975 film
- The Book of Eli 2010 film