The EMP Grenade is a secondary weapon used only by the player. When thrown, it will explode into a much larger version of the Recruiter Grenade's particle effect. Any bot within the radius of this "explosion" will be shut off for an average of 10 to 15 seconds, with the exception of a player. If a player walks into the radius of the grenade their screen will spiral out of control, causing their aim to be much less accurate.
In-game description of the weapon: "Emits an electromagnetic shockwave in all directions that disrupts cognitive and mobility circuits in nearby Mils." (However in the actual game, the EMP grenade affects Droid bots as well.)