* Mewtwo isn't in FireRed: Mewtwo is not available in the original Pokemon FireRed game.
* Shiny Hunting Requires Encounters: Shiny Pokemon are rare variations that appear randomly. To find a shiny, you need to encounter the Pokemon in the game, and there's no way to encounter Mewtwo in FireRed.
Here are some ways you can get a shiny Mewtwo in other Pokemon games:
* Pokemon Let's Go, Pikachu! & Eevee!: You can encounter and potentially catch a shiny Mewtwo in these games.
* Pokemon Sword & Shield: You can find Mewtwo in Max Raid Battles and potentially encounter a shiny version.
* Pokemon Brilliant Diamond & Shining Pearl: You can find Mewtwo in the post-game and potentially encounter a shiny version.
* Pokemon Omega Ruby & Alpha Sapphire: You can find Mewtwo in the post-game and potentially encounter a shiny version.
Important Note: Shiny Pokemon have a very low chance of appearing (approximately 1/4096). This means you'll likely need a lot of patience and luck to find one!