The Mechanist's Costume

The Mechanist's costume and the matching The Mechanist's helmet are pieces of Fallout 3 armor worn by the eponymous self-proclaimed superhero, the Mechanist, who is hiding out in the Robot Repair Center south of Canterbury Commons in the Capital Wasteland.

Location
The armor can be obtained either by killing the Mechanist or persuading him to give up his career.

Related quests
Should you be asked by Uncle Roe to solve the town's "Superhero" problem, The Mechanist's costume can be handed over to the AntAgonizer to end the town's problems. Alternatively, wearing the costume in the AntAgonizer's presence will turn her hostile.