Here's how you can get Spiritomb, and thus a shiny one:
1. Find 107 Wisp of Spirits: These are scattered throughout the world and you need 107 of them to unlock the encounter.
2. Go to the "Odd Keystone" location: This is a specific spot in the game where the Spiritomb is waiting.
3. Use the 107 Wisp of Spirits: When you interact with the keystone, you'll be able to summon Spiritomb.
4. Check for shiny: Once you've summoned Spiritomb, it has a chance of being shiny.
Important Notes:
* Shiny odds: The standard shiny rate applies, which is approximately 1/4096.
* No "guaranteed" shiny method: Unfortunately, there's no method to guarantee a shiny Spiritomb. You'll have to rely on luck!
* Different games: The location of the Odd Keystone and the method of obtaining the Wisps of Spirits can differ between Pokemon games.
If you're playing a specific Pokemon game, it's best to look up the specific instructions online for obtaining Spiritomb in that game. Good luck with your shiny hunt!