Clock King is a DC comics villain dating back to 1960, and was originally an enemy of Green Arrow. Though he's sometimes been portrayed as flashy and gimmicky, there are are more subtle portrayals, and he achieved a degree of popularity as a Batman villain in "Batman: The Animated Series." There have been multiple characters to don the Clock King mantle and he doesn't have a definitive characterization or origin, nor a definitive costume-- he would be a perfect candidate for a villain to be re-imagined in Arrow, and could certainly be handled in a more grounded, street-level way. The producers could go any number of directions with his time motif. Given that "Arrow" hasn't shied away at all from both familiar and more obscure comic book characters, it would be a wasted opportunity not to include a new incarnation of one of the earliest and most fun Green Arrow villains. Include the Clock King as an adversary for Oliver Queen in "Arrow!"