Star Trek: 10 Alien Races That Only Appeared Once

10. Voth

One of Voyager's best alien creations and a sci-fi cheese classic if you read the synopsis as Dinosaurs in Space.

The opening 15 minutes are devoid of the principle cast. The audience instead follows Doctor Gigen as he explores the Distant Origin Theory that the Voth were not originally from the Delta Quadrant but somewhere else entirely... Earth.

It's a revolutionary move for Star Trek to leave an episode in the hands of its guest cast but it thoroughly establishes the race, their background and significance of humanity in relation to them.

While echoing Galileo's trial, at which he argued that the Earth revolved around the Sun, Distant Origin goes much further. The concept of a super-advanced civilisation flying city-sized ships makes for compulsory watching, so tie this in with the trial of their own scientist for his proven findings and you have a Voyager classic.

The revelation that they were from a far part of the galaxy could have disrupted their society inexplicably especially when explained they were DNA relations to the "lesser" humans.

Their story has been continued, like the Vaadwaur, on Star Trek Online engaging them as a serious Delta Quadrant threat.