[Nate the Great]

October 6th, 1967, "Mirror, Mirror"

First let me say how gratifying it is that this episode has led to who knows how many parodies and riffs in all kinds of shows over the year, and "the evil alternate with a goatee" has entered pop culture.

Second, no mentions of Enterprise or Sato clones, please.

The Fiver (by IJD GAF)
Transcript
Memory Alpha

The Episode

Captain's log, stardate unknown. During an ion storm, my landing party has beamed back to the Enterprise and found it and the personnel aboard changed. The ship is subtly altered physically. Behaviour and discipline has become brutal, savage.

I hope this log was recorded on something heavily classified. Furthermore, the Captain's Log is supposed to be accessible to all Starfleet officers, right? Shouldn't Kirk at least use an encrypted personal log? Unless you're a fan of the postwritten log theory.

KIRK: Get to your post. Run today's communication from Starfleet Command. I want to know my exact orders and options, if any.

Today's communication? I never got the idea that Starfleet Command sent daily communiques to their ships, talk about micromanagement!

SCOTT: The two-way matter transmission affected the local field density between the universes, and it's increasing. We've got to move fast.

Yesterday Scotty didn't know that this parallel universe even existed, and now he completely understands the "local field density" between them?

SPOCK: May I point out that I had an opportunity to observe your counterparts here quite closely. They were brutal, savage, unprincipled, uncivilised, treacherous, In every way, splendid examples of homo sapiens, the very flower of humanity. I found them quite refreshing.
KIRK: I'm not sure, but I think we've been insulted.
MCCOY: I'm sure.

So am I, Bones. So am I.

The Fiver

Kirk: Scotty, just get to engineering and short out the phaser circuits. Uhura, go flirt with Sulu or something. And McCoy... I dunno, just stand there and look boring.
McCoy: I'm a doctor, not a doorstop!

Classic gag from First Contact. The thing is, I'm not in the camp that puts that movie near the top of the list. Too much violence, and Picard in Ahab mode is simply annoying.

Mirror Marlena: It's Jim Kirk, my love and my master.
Kirk: This has got to be a speed record for me.
Mirror Marlena: You almost got killed and you're disobeying orders. (smacks Kirk in the head) Stupid!
Kirk: My second speed record this scene.

Reminds me of a SF Debris gag where Kirk is slapped and declares an increased arousal level every time in confusion.

Memory Alpha

* The scriptwriter based the idea on a short story he wrote over ten years earlier.
* A similar idea was part of Roddenberry's original series proposal.
* This episode marks the first time a Trek actor (Takei) has worn all three division colors, although this includes alternate versions.

Memory Beta

* Mirror Kirk recurred in the Shatnerverse novels. It's revealed that he got the Tantalus Field from Mirror Balok.
* Mirror Spock apparently used the Tantalus Field to gain power. That doesn't seem to fit his personality, does it?

Nitpicker's Guide

* Wouldn't a starship built by the warlike Terran Empire be better armed, with a different design?

YouTube

Star Trek Continues revisits the Mirror Universe
Kirk convinces Mirror Spock to overthrow the Empire
The ending, including Spock zinging humanity and the Marlena cameo that was reused in Trials and Tribbleations
Uhura tricks Mirror Sulu
The TNG intro as if it was set in the Mirror Universe (many shots from the alternate timeline of "Yesterday's Enterprise" were used)