Long Lost Alien Species

[crystal]

I think you might know the ones I'm talking about--they're the Star Trek species' that have appeared maybe only once, and then we never saw anything from them again. I don't mean peoples like the Romulans or Vulcans or Klingons, because we have seen quite a lot of them.

The ones I'm talking about are like the Horta, which only appeared in one episode. Also the Medusa, which was, to me, a fascinating race which appeared only once. And I'm sure the list goes on and on.

So how about it? Care to discuss or at least mention some long-lost or forgotten alien races from Star Trek? >.>

[Mandalorian]

Tribbles! of course we have seen those a good number times... oh and there was the greek race (i can't remmber there name) the ones with the telekentic powers, i liekd that episode alot.

[Junk Angel]

Or that race, that created all the others from their genetic material.

[Xavier Harkonnen]

Gorn!
2 episodes!