- Star Trek: The Motion Picture
- Star Trek II: The Wrath of Khan
- Star Trek III: The Search for Spock
- Star Trek IV: The Voyage Home
- Star Trek V: The Final Frontier
- Star Trek VI: The Undiscovered Country
- Star Trek Generations
The long-dead species and culture of a subtrerranean humanoid civilization from a still-fertile world in the Delphic Expanse, based in the city of Urquat. Somehow rendered sterile, the people tried to continue by developing a mutagenic virus that converted victims of any species to Loque'que DNA — a virus that still lives to torment unwitting visitors. Tret's people, adifferent species, have been increasingly obsessed with its eradication (as well as all carriers) for over 60 years.