Pokémon Red and Green beta
Pokémon Red and Pokémon Blue were the first Pokémon games to be released in the US, on September 30, 1998. Several beta elements of the game have been found in the game itself and also on the Internet.
PROF OAK wants to fight
Professor Oak, the character in the game who gives you your starter Pokémon, has a full team of Pokémon programmed into the game, although the battle cannot occur during a normal game. The player must use a GameShark code. Professor Oak has a Tauros on level 66, an Exeggcutor on level 67, an Arcanine on level 68, a Blastoise on level 69, and a Gyarados on level 70. He can also be battled in Pokémon Yellow.
The BLUE wants to fight
Before Red and Blue's US release, screenshots were released of a rival battle with the text "The BLUE wants to fight". In the final version, "the" is dropped. While this text would work with "The LASS" and "The HIKER", it would cause problems with "The BROCK" and "The MISTY".
NICKNAME?
A beta item that allows the player to walk through walls in the game is accessible via a Gameshark code. The item, which shows up in your pack as "NICKNAME?", is speculated to be a beta object testers used to quickly move forward through the game.