In the distant Koprulu Sector of the Milky Way, Facebook’s Zerglings lingered in a restless swarm outside the enemy’s base. After the commander ill-advisedly opened the gate, the social network’s alien horde stormed in and slaughtered forces stationed inside, in a battle fought on the frontiers of artificial-intelligence research.

The bloody incident was part of an annual competition of the videogame StarCraft for AI software bots that wrapped up Sunday. Facebook quietly entered a bot called CherryPi designed by eight people employed by or affiliated with its AI research lab.

The social network’s stealthy space war suggests Facebook is serious about competing with Google and others to set showy new milestones in AI smarts. Google’s London-based DeepMind AI research unit made headlines last year when its AlphaGo software defeated a champion at the board game Go. In August, DeepMind declared StarCraft II, the latest version of the game, as its next target.

The contest Facebook entered, like most AI research in the area, used an older version of StarCraft, which is considered equally difficult for software to master. Facebook’s AI research group, which lists 80 researchers on its website and is led by NYU professor Yann LeCun, has produced many research papers but not notched up an achievement as striking as Google’s with Go. Facebook has released three research papers on StarCraft, but not announced a special effort to conquer the game.

Final results released Sunday indicate Facebook still has a way to go: CherryPi finished sixth in a field of 28; the top three bots were all made by lone, hobbyist coders.

Gabriel Synnaeve, a research scientist at Facebook, described CherryPi to WIRED as an "baseline" on which to build future research on StarCraft. "We wanted to see how it compares to existing bots, and in particular test if it has flaws that need correcting," he said. CherryPi competed in a long-running contest that is part of AIIDE, an academic conference on applying AI in entertainment. Facebook also sponsored this year’s contest, paying for hardware used to run the thousands of bot-on-bot games.

Games such as tic-tac-toe, checkers, chess, and Go have been testbeds for new ideas in artificial intelligence since the field’s beginnings in the 1950s. These days, there’s also a serious business purpose, as companies increasingly use AI to hone their product and service offerings. Facebook, Google, and other tech companies use AI to improve ad-targeting and personalization systems, and enable new products, such as virtual assistants and augmented reality.

StarCraft is alluring to AI researchers for more than just the fun of commanding weapons like the building-leveling Yamato plasma cannon. Although the videogame may appear more approachable than Go or chess, it is many times more complex, because players’ pieces and actions aren’t limited to a tightly regimented board and always in full view of their opponent. The number of valid positions on a Go board is a 1 followed by 170 zeros. Researchers estimate that you’d need to add at least 100 more zeros to get into the realm of StarCraft’s complexity.

The winning bot in this year’s competition, ZZZKBot, was made by Chris Coxe, a software developer in Perth, Australia, who previously worked for NASDAQ. He built his bot alone, and lately took a break from work in part to dedicate more time to it. A day before the final results were announced, Coxe spoke self-deprecatingly of his handiwork. “It was supposed to be a proof of concept,” he said. “The source code isn’t all that great.”