In the early 2000s Earth launched the space probe Nomad, designed by Jackson Roykirk to seek new life; altered by an alien probe, it resurfaced in 2267.
Nomad was an early interstellar probe built under the direction of Jackson Roykirk to search for other forms of life. Soon after launch it was believed destroyed. In fact it had been damaged and then merged with Tan Ru, an alien probe designed to sterilise soil samples, producing a machine devoted to eliminating imperfect life.
In 2267 Nomad wiped out the population of the Malurian system and was brought aboard the Enterprise, where it mistook Kirk for its creator. Kirk persuaded it that it had made errors, and Nomad destroyed itself according to its own directive.