In shows with a lot of standalone episodes, one of the consequences that crops up is that a concept introduced in one episode ought to have really, really huge implications for the universe. Like, enormous. We’re talking world-changing at the very least. And yet, the events of that episode are rarely ever brought up again. So here we go, 4 episodes that should’ve been rocking the foundations of these shows, but went by practically unnoticed.

4. “The Christmas Invasion”–Doctor Who

Doesn’t that seem like the kind of thing that might come in handy later?

Okay, so this whole trope is pretty much Doctor Who‘s M.O. The Doctor doesn’t usually cart all the neat shit he sees around. Where all that turns around, however, is when Torchwood is introduced in season 2. Now, it’s the humans of modern day Earth collecting all this alien technology that keeps raining down on them every year (usually suspiciously near Christmas). At the end of this episode, Prime Minister Harriet Jones (yes, we know who she is) uses a Torchwood weapon to destroy the Sycorax ship leaving orbit, earning the Doctor’s wrath. But when the Racnoss come around next Christmas, where’s that giant laser? Or when that giant space Titanic almost crashed? Sure, Torchwood itself was mostly destroyed, but it wasn’t gone completely, and even if it was, that’s no reason why the laser would be. It’d almost certainly be taken over by UNIT, rather than just left lying about.

At least with this one, we can chalk up the lack of use beyond a certain point to the differences caused by the cracks in the universe from series 5 (which was a pretty huge retcon itself). The other examples on this list aren’t quite so fortunate.

3. “A Voice in the Wilderness”–Babylon 5

It’s a real shame B5 isn’t on any of the streaming services right now…

In this episode, the Great Machine is revealed deep under the surface of the planet that Babylon 5 orbits. The Great Machine is a ridiculously powerful device, constructed by unknown beings, and we get a small taste of its power in the episode when it destroys Takarn’s ship in a single blast. The being occupying the Machine from this point forward is Draal, a friend of Delenn’s who promises to help them whenever possible.

Now, while they do utilize the communication abilities of the Machine throughout the series, and they set up a base for a while, its weapons are almost never used, even when massive battles for the fate of the galaxy are taking place all around. We also never really found out who made it or why, which is one of the big outstanding mysteries of the franchise (perhaps it’d have been touched on in Crusade?). It’s pretty clear from a writing perspective why it wouldn’t be used, as even the Shadows would have a hard time challenging the Machine’s power. It’d be too much power in B5’s corner.

2. “Unnatural Selection”–Star Trek TNG

Their “perfect” kids are a little, uh… lacking diversity.

Since Star Trek Voyager‘s “Threshold” has been unofficially stricken from the canon, that leaves this as one of the more egregious moments in the franchise. This episode focuses its plot on a scientific research station where they’re studying genetics, something which is widely regarded in the Star Trek universe as a horrible thing that should not be done. Except in this episode, where the Federation is conduction this research to create little genetically perfect human babies–actually, going a step farther than the Augments ever did, by giving them immune systems so aggressive they attack threats even beyond the body and psychic abilities. The consequences of these developments are huge for the Federation, and given that they were even allowing this research to be performed in the first place, they must have had some sort of plan to follow through on it. Even if we discount the aggressive immune system, which was the root of the mystery in this episode, the capability to unlock telepathic abilities in humans with genetic engineering alone should be an immense revelation. These aren’t just weak empathic powers like Troi’s, either, but full-blown telepathy and telekinesis–as in, moving physical objects with their minds.

But no, the consequences of this discovery are swept under the rug and never brought up again. Oh well!

1. “Unending”–Stargate SG-1

The entirety of their knowledge right there. Holograms, energy weapons, the works.

SPOILERS FOR SG-1 FINALE AHEAD.

In the final episode of SG-1, the Asgard make a decision to hand over everything they’ve learned to the humans of Earth, in the form of the Asgard computer core. The rest of the events of the episode aside, this is absolutely massive. It’s the kind of thing you’d expect to have happen in the finale, catapulting Earth’s technology ahead by not just centuries, but likely millennia. Which, if the universe had ended with the series finale, great! Awesome way to end the series.

The problem was Atlantis was still running (for a little while, anyway) and Universe was about to start up, as well as the direct-to-dvd followups for SG-1, so having that overpowered Asgard core waiting in the wings would’ve given the Earth in those shows a ridiculous advantage. Watching the Hammond get its butt kicked by the Lucian Alliance in Universe‘s premiere was already tough to believe, but knowing that there was Asgard tech around to buff it up makes it especially ridiculous.

So that’s it for this week. Sorry it was a little late. As always, you can message me on Twitter if you have any suggestions @RetroPhaseShift. Monday will bring us back to A Subjectively Obscure Sci-Fi Primer, so be sure to return then!