District 9 was one of the most successful movies of 2009. It was nominated for 4 Academy Awards including Best Picture. Written and directed by Neill Blomkamp and produced by Peter Jackson.
The bio-suit (also called a mech prawn), as the name says, is a mech used by the Prawns to defend, attack or help in construction and repairs.
Inside the machine, the operator has complete control over a wide variety of tools and weapons on the suit which is all controlled via the highly advanced heads-up display. The mechanized suit could presumably be used for tasks such as ship and technology repairs, but the suit also has a wide arsenal of highly dangerous offensive and defensive weapons. The suit has been shown to possess a larger version of the ARC gun, a machine gun, rocket launchers and a metal spike that drives into the enemy and sends a charge through them that eventually causes them to explode. The suit can also activate certain weapons on its own when a prawn (or one with prawn DNA) is attacked. Once it eliminates all threats to the threatened prawn, the cockpit opens allowing the prawn to climb in and use the mech for self-defense.
In this scene from District 9, finding himself surrounded, Wikus uses the suit to escape and rescues Christopher Johnson. Wikus covers Christopher until he’s close to the dropship, but is forced to have Christopher go on without him as the suit has by that point taken a lot of damage and can’t go very fast anymore. Wikus uses the suit to battle MNU’s forces, killing all but their leader Venter, but after getting shot multiple times, including with a high-powered sniper rifle, had its left hand blown off by a rocket and rammed twice with trucks, the suit breaks down and ejects Wikus.