Kraal

The Kraals are a sapient species from the planet Oseidon, a world plagued by an ever-increasing level of radiation. In the 20th century, knowing that their planet would soon be uninhabitable for them, the Kraals tried to invade Earth using android replicas to infiltrate the Human population and unleash a deadly virus.

Appearances

 * Doctor Who, season 13, The Android Invasion (1975)