The Dark Knight (2008)
The Joker intervened the mob-boss’ secret meeting to offer his uique skill set service…
The Chechen: What do you propose?
The Joker: It’s simple. We, uh, kill the Batman.
Salvatore Maroni: If it’s so simple, why haven’t you done it already?
The Joker: If you’re good at something, never do it for free.