Dark persona of Link from The Legend of Zelda series.
He first appeared as the last boss of Zelda II: The Adventure of Link. In this form he appears as Link's shadow: a completely black figure with Link's profile.
Dark Link reappears as the Water Temple midboss in The Ocarina of Time. A fan favorite fight. In addition to being three-dimensional, he now comes in varying shades of black and dark gray and has red eyes.
Also an antagonist in the GBA remake of A Link to the Past. Bonus boss in Spirit Tracks.