lethal specimen

A term used to refer to somebody that is capable of inflicting high amounts of harm and damage upon any unfortunate person that happens to anger them; an absolute weapon; the hard man of the town. These types of people, from whom I advise that you stay at least 500 kilometres away, are incredibly dangerous and can win a fight against even the toughest silverback gorilla.

Josh: "Fuck you."
Harley: "Woah. Lethal specimen."