- Aliens Speaking English: Lampshaded.Mace: You can understand our language.
Alien: And the rest about you. Your spur is fear. Your answer is destruction. You would destroy us and we have done no harm.
- Becoming the Mask: The premise of the episode. Mace goes from simply being undercover as a space alien to actually feeling more comfortable in his skin as one of them.
- Benevolent Boss: Chambers, who speaks highly of Mace and always has his well-being in mind.
- Big "NO!": How one of the aliens reacts when Mace kills the other.
- Chromosome Casting: This is one of two Outer Limits episodes with all-male casts ("The Invisible Enemy" is the other).
- Deep Cover Agent: Mace was one of these before he was "compromised" and had to leave the spy business.
- Desperately Looking for a Purpose in Life: Once Mace is forced out of his old life as a spy, he doesn't know what to do with himself. This is why when Chambers offers him a new assignment, he jumps at the call despite having no idea what it involves.
- Does Not Like Shoes: The aliens go barefoot.
- Earn Your Happy Ending: Mace has spent his career as a spy and an assassin, despite knowing that he wants to create rather than destroy. Now, he's found happiness by overcoming his destructive urges and joining the kindly aliens on their home planet as one of their own.
- Easily Forgiven: At the end, the surviving alien forgives Mace for killing his companion, especially when Mace shows remorse for his violent actions.Mace: Would you still have me come along with you?
Alien: It's a long journey to my planet. It would be better to make it with a friend.
- First Contact: It's accidental, and it doesn't go the way anyone wanted or expected.
- Good All Along: The aliens who crashed landed on Earth seemingly possessed nuclear weapons. But it turns out that not only did they give false readings of possessing any weapons at all, they actually come from a peaceful planet without war.
- Humans Are the Real Monsters: But in this story, they redeem themselves by admitting it and changing their ways.
- Killing in Self-Defense:
- Why the aliens attacked the human soldiers.Mace: You killed those men on that patrol.
Alien: They tried to kill us.
- Also, the first thing we see Mace do is use a flyswatter to strangle an assassin who tracks him down in a Mexican bar.
- Why the aliens attacked the human soldiers.
- My God, What Have I Done?: Mace has this after he kills one of the aliens after Chambers' signal triggers his assassin instincts. It takes a while for him to realize what he's doing is wrong, but eventually, it sinks in.
- No Name Given: Applies to the individual aliens, their race, and their "warm yellow planet".
- Reasonable Authority Figure: General Crawford proves himself to be one when he lets Mace leave with the alien, despite his own objections.
- Seen It All: One reason why Mace became disillusioned with his life as a spy.Mace: The mission calls for an experienced agent. There are very few experiences I haven't had. On the plane, Mr. Chambers promised me a new experience. Whatever it is, I'll welcome it.
Recap / The Outer Limits S 1 E 31 "The Chameleon"