Called 'Man vs Machine', the mode pits a team of six players against waves of computer-controlled robots. Each wave will also have a bomb carrying robot, giving boosts to nearby robots and ending the round if it reaches the player base.
The robot army consists of metal variations on the standard Team Fortress 2 classes. For example, one type of robot sniper specializes in accuracy, while another fires jarate-coated darts.
Some waves will also include giant robots, such as a soldier with a rapid-fire rocket launcher and a heavy that can deflect projectiles.
The new mode will launch as a free update to Team Fortress 2 through Steam on Wednesday (August 15).
Watch the 'Man vs machine' trailer for Team Fortress 2 below: