A couple of the early episodes referred to "lithium crystals" as an essential component of the Enterprise's engines. This was later changed to the better known (within the context of Star Trek) "dilithium crystals", because the writers realised too late that lithium was a real material and didn't have any of the properties they ascribed to it in the series.

It's interesting that for one of the most valuable materials known, a planet where it can be found is inhabited by just three miners.

This strip, by the way, marks the first (future) cross-over with Shaenon Garrity's X-Files recap comic, Monster of the Week! Ben Childress is played by Gene Dynarski, who would later go on to play Ernie Stefuniak in The X-Files eighth season episode "Patience". As this comic is published, that episode is still in the future for Monster of the Week, but I am confident we'll get to see it.

Transcript

1
Captain's log, Stardate 1329.8. The Enterprise is pursuing an unidentified vessel.
2
Spock: Asteroid belt, Schiller rating three five.
Kirk: Meaning?
Spock: 2³⁵ denser than a real belt.
3
Scotty: Captain, we've saved one man dressed as a... Well, far be it from me to judge. And three... crew.
Harry Mudd: They're not crew, they're me cargo!
Caption: Actual line!
4
Caption: Awkward pause while male crew stare at the women.
SFX: slinky music
Caption: Even the medical scanner is affected!
5
Harry Mudd: I'm Harry Mudd and I recruit wives for settlers.
Kirk: Hmm. I know some Ents who'd be keen to meet you.
6
Scotty: We burnt out three lithium crystals. The last one won't last long.
Spock: There's a lithium mine on Rigel XII. Manned by just three lonely men.
Kirk: Allons-y!
7
Magda: Harry! The pills are wearing off!
Ruth: We're ugly! We need the drug!
Harry Mudd: Here you go.
8
Caption: Direct cut to:
Spock: {holding a lithium crystal} Even burnt and cracked, they're beautiful.
Caption: Holy subtle allusions, Batman!
9
Caption: On Rigel XII:
Childress: Eve went crazy and ran off into the sandstorm.
Kirk: I'll find her. No need for anyone less important than the captain to risk their lives.
10
Childress: Now she's ugly! I don't want her cooking and cleaning for me!
Kirk: Take the Venus drug, Eve.
11
Eve: I'm beautiful again.
Kirk: It was a placebo! Your own self-confidence makes you beautiful.
Spock: And does your make-up and styles your hair.
12
Eve: We'll stay here and marry the miners.
Kirk: Okay. Spock, let's go.
Harry Mudd: Can I stay?
Kirk: No, you have a trial coming. And I'm afraid your name is—
Caption: Cue end credits!