Kyogre

Description
Kyogre is Misty's star Pokémon. At the end of Cerulean Gym, she calls out a Kyogre in front of Joey and Maruto. Later it is mentioned that Mewthree was controlling Kyogre which in turn was actually controlling Misty, and by defeating Kyogre Misty is released as well. Unfortunately, it isn't catchable and never will be unless hacked. Kyogre is in the possession of Maruto, as stated in the cutscene of Route 24, so it can be transported to Cinnabar Island. Once you have defeated Cinnabar Island, he will leave for Pallet town to see Professor Oak.

Location

 * Cerulean Gym: Cutscene
 * Cerulean Gym 2: Boss Uncatchable, Cutscene
 * Route 24: Cutscene
 * Route 19: Cutscene, On Background
 * Cinnabar Island: Cutscene, Background Capture.png
 * Cinnabar Gym: Cutscene

Trivia

 * Some people hacked the game in order to obtain Kyogre, so Sam banned Kyogre in the trade system.
 * In the v3.2 update, Sam transferred everyone's accounts which had over 800,000 Pokémon. 7,000 of them were Kyogre, which were deleted.
 * In Cerulean Gym 2, if you use Transform your Pokémon will transform into Kyogre.
 * Kyogre is currently the first of two 3rd Gen Pokémon to ever be in the game, although only as a boss. He is also the first non-1st Gen Pokémon to appear in the game (followed by Celebi, the Legendary Dogs, Groudon, and Victini).