- 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
Origin: Gamma Quadrant. Two humanoid factions of the same species who fought for so long they were banished to a prison moon to continue their fighting, able to finally die only if they escape the prison due to special microbes placed in the moon's atmosphere which rebuild injuries and prevent anyone who dies on that moon from leaving it.