In Dark City, the alien race that experiments on humans is called the Strangers.
The Strangers are the hidden rulers of the film’s perpetually dark city. They are extraterrestrial beings who occupy dead human bodies and share a collective, hive-like consciousness. Their goal is to understand individuality and human identity, because their own race is dying and they hope to discover what makes humans adaptable.
At midnight, the Strangers put the city’s inhabitants to sleep, reshape buildings and streets through a power called tuning, and alter people’s memories. They then give residents new identities and life histories, creating controlled social experiments. John Murdoch becomes especially important because he develops tuning abilities of his own and awakens before the Strangers can complete one of their memory implants.
The name can be confused with generic labels such as “the Visitors” or “the Others,” but those are not the film’s canonical term. The Strangers’ pale appearance and identical clothing emphasize their shared identity, while individual figures such as Mr. Hand and Mr. Book serve as members or leaders of the group.