Dark Naruto

Evil Naruto is a dark reflection of Naruto Uzumaki born from the demon island's "Falls of Truth".

Fourth Shinobi World War arc
After Killer Bee refuses to train Naruto, Motoi guides Naruto and Yamato to the "Falls of Truth", the place where Bee trained to control his beast. He instructs Naruto to sit in a platform and close his eyes so Evil Naruto appears, berating Konoha's people for how quickly they changed their ideals of Naruto and have started sucking up to him which sickens him.

It is unknown if this is a physical manifestation, or merely a mental one.

Trivia

 * "Evil Naruto" is a fan name given to said character given the reasons behind his creation.