Pokemon Yellow: Professor Oak Battle
A battle against Professor Oak in Pokémon Yellow. This is a glitch activated when a Gameshark code is used. He was initially supposed to be in the game after defeating the champion going by his team but was then not included in the actual games.
His team consists of:
Tauros L66
Exeggutor L67
Arcanine L68
Venusaur/Charizard/Blastoise L69
Gyarados L70
Gameshark Code ~ 01E22DCD
Soundtrack ~ Pokémon Black & White: Elite Four Battle