Jack is a COG JACK-series robot from the Gears of War video game series. Like other bots of its class, Jack was designed for general assistance, such as conducting maintenance and repairs on machinery, minor medical applications and surveillance. During humanity's war against the Locust Horde, Jack had been assigned to Delta Squad under Sgt. Marcus Fenix. Delta Squad would often have Jack use its cutting tools for ripping open locked doors, conducting vehicle repairs, or would use Jack as a communications relay to keep in touch COG Control.
- Levitation - Jack's means of locomotion was an anti-gravity unit that allowed it to hover everywhere.
- Cutting/Welding Tools - Jack would use these tools for electronic maintenance, repairing vehicles or simply opening locked doors.
- Cloaking Device - Jack was capable of bending light around itself, becoming invisible. This allowed it to traverse hostile territory without being targeted by Locust forces.
- Taser - In Gears of War 3, Jack was modified with a taser for stunning Locust soldiers, making it easier for Gears to kill them.