Doctor Who and the Krikkitmen
Krikkit was a planet at the far edge of Mutter’s Spiral. Surrounded by an enormous dust cloud, the native Krikkitas believed it to be the only location in the universe. Hactar, a supercomputer who was created by the Alovians to destroy the universe but failed, hatched an intricate plan using Krikkit to execute his original mission. (This in turn was influenced by the First Great War TARDIS, wanting to free the other War TARDISes.) Hactar sent a replica spacecraft to Krikkit, alerting the Krikkitas of the outside world. Xenophobically unwilling to accept the existence of other life, the Krikkitas set out to commit universal genocide. Using the technology found in the spacecraft, they mass produced android warriors known as the Krikkitmen and started the Great Krikkit War.
Eventually, the Time Lords intervened and placed Krikkit and its sun in a Slow Time envelope which would hide the planet from the universe (and vice versa) in a slowed down state of time, only to be released at the end of the universe when all else had decayed due to Entropy. The Slow Time field was locked using the Wicket Gate, a key comprised of several components scattered across the universe. The rest of the Krikkitmen were imprisoned on Shada.
Millions of years later, several rogue Krikkitmen attempted to reassemble the Wicket Gate. The Fourth Doctor, Romana, and K9 tried to stop them, but failed to do so in time. They decided to visit Krikkit to try to change the Krikkitas’ minds. During the time in the envelope, the Elders of Krikkit had attempted to reproduce more Krikkitmen, to no avail. However there were some hesistant rebel factions, who helped The Doctor. The Krikkitmen began to launch another massacre on the universe, but The Doctor tricked them into repeatedly switching on and off until they overloaded. In the end, the Krikkitas were convinced to create a religion by Richfield and Wedgwood. (Doctor Who and the Krikkitmen)