Unlock Sonic and Tails
In December 2001, Nintendo released a fight game for their GameCube system called "Super Smash Bros. Melee" that let you play and battle any of 25 or so different characters from past Nintendo games, including Mario, Luigi, Princess Peach, Donkey Kong, Zelda, Link and Pikachu. It was believed by some that you could even play two characters from another system: Sonic and Tails from Sega's "Sonic the Hedgehog." As unlikely as that seems, some credence was lent to the rumor by the fact that Sega was, indeed, starting to license their characters to third-party game developers around that time.
An issue of popular game magazine Electronic Gaming Monthly printed an article stating that you could unlock Sonic and Tails as playable characters by achieving 20 knockouts in Cruel Melee mode with any one character and then beating Sonic and Tails when they appeared and challenged you. It even hinted at a "special surprise" if you finished Classic mode with either of the characters. Many a player tried this arduous task and failed. Unfortunately for them, that Electronic Gaming Monthly issue was from April 2002. It was all just an April Fools' joke. Nintendo did, however, include Sonic in games years later, starting with "Super Smash Bros. Brawl."