The Hidden Triforce
The Triforce was an item in Nintendo's Zelda games that granted the holder great power, and finding and assembling its pieces was a major plot point in the original game "The Legend of Zelda." It looked like a metallic triangle made up of three smaller triangles. The item also had an influence on the plot of the 1998 game "The Legend of Zelda: Ocarina of Time."
Before "Ocarina of Time" launched, Nintendo released promotional material that included an image of the Triforce. And on the Quest Status screen in the released game, there appeared to be a spot for it in the middle of a ring of Spiritual Medallions. These things understandably led people to believe that the Triforce would be somewhere in the game for the taking, and many methods for locating it were concocted and spread. As with other gaming myths, photographic evidence even appeared. But those pictures were hoaxes, and all searches for the Triforce were fruitless, because the item was nowhere in the game. The Quest Status screen Triforce logo was just decorative, and the promotional material was just that, not actual in-game reality. Nintendo got enough queries about it that they tell players it doesn't exist in the game's online FAQ.