Doppelganger

Doppelganger is the seventh episode of Legend of Zelda animated series. It first aired on October 20, 1989.

Synopsis
Ganon plants a magical mirror in Princess Zelda's room, which copies her reflection into an evil clone of her. The real Zelda is captured by Ganon's henchmen and the evil clone remains in Zelda's place. The evil clone tricks Link into taking the Triforce of Wisdom to Ganon's castle, although on the way Link realizes the truth about the evil clone as she has no reflection.

Link continues to the castle anyways to confronts Ganon. He rescues the original Zelda, although both Zelda and the evil clone of fall into muddy water and Link has to figure out which is the real Zelda and which is the fake. He decides to determine this by a "kissing contest", and when one Zelda refuses to kiss him, he knows that she is the real one because the evil clone has kissed him several times. Link zaps the evil clone and he escapes with the real Zelda using the Triforce's magic.