Igrix

Igrix was a Kustollon.

His people engaged in a war with Earth in 3045, which devastated both sides. He stole a time machine and travelled back to the 1960s. He wanted to make humanity content so they would not advance technologically, thus saving both sides in the future. However, he did this in part by killing scientists whose inventions would accentuate mankind's aggressiveness.

The Ninth Doctor stopped his plan and infected Igrix's ship with a "human virus". This made it independent and the ship decided to explore the universe, with Igrix unable to control it at all. (COMIC: The Love Invasion)