The Freakshow is the name of a gang of cybernetic punks that terrorize various parts of Paragon City.
For the Freakshow, metal is power. The more metal they have, the more powerful they are.
For the Freakshow, heavy metal music and body piercings are baby steps. "Dethklok is a joke!" they often scream out.
They don't just want to WEAR metal. They want to BE metal.
To that end, they do everything in their power to get metal devices fashioned. They will chop off their own limbs to replace them with metal objects. They will pump themselves up with Superadine, or any of its various derivatives, to give themselves added power. They will even use Rikti technology to make themselves powerful.
(Please see their Paragon Wiki entry for more information.)