+

 Evil twin

The evil twin is an antagonist found in many different fictional genres. They are physical copies of protagonists, but with radically inverted moralities. In filmed entertainment, they can have obvious physical differences with the protagonist—such as facial hair (often a goatee), eyepatches, scars or distinctive clothing—that make it easy for the audience to visually identify the two characters. Sometimes, however, the physical differences between the characters will be minimized, so as to confuse the audience. Both roles are almost always played by either the same actor or the actor's actual twin (if the actor has one).

Though there may be moral disparity between actual biological twins, the term is more often a misnomer. In many cases, the two look-alikes are not actually twins, but rather physical duplicates produced by other phenomena (e.g. alternate universes). In others, the so-called "evil" twin is more precisely a dual opposite to their "good" counterpart, possessing at least some commonality with the value system of the protagonist.