The Pokémon Company has announced a Shiny Lucario event Pokémon distribution for Pokémon Scarlet and Violet. It is available from December 7th, 2023 until January 3, 2024, at 3:59 p.m. PST. The password is: SH1NYBUDDY

Add a Shiny Lucario to Your Team

Use this password to have the Aura Pokémon fight its way into your Pokémon Scarlet or Pokémon Violet game.

Add some intensity to your Pokémon Scarlet or Pokémon Violet team with a Shiny Lucario! This Lucario knows a variety of useful attacks, so it’s sure to come in handy on your adventures. Enter the password below via Mystery Gift and harness Lucario’s powerful aura prowess.

Password: SH1NYBUDDY

This password expires on January 3, 2024, at 3:59 p.m. PST.

Source: https://www.pokemon.com/us/pokemon-news/add-a-shiny-lucario-to-your-team

A Shiny Lucario Appears!

Add a Shiny Lucario to Your Team and Bring It along on Your Adventures
You can now receive a powerful partner to accompany you on your adventures: a Shiny Lucario! This Lucario comes with a variety of useful moves that are sure to come in handy.

Password: SH1NYBUDDY
This password expires on Wednesday, January 3, 2024, at 23:59 UTC.

How to Receive Shiny Lucario

Use these steps to claim your in-game gift.

1. Launch your Pokémon Scarlet or Pokémon Violet game.
2. Select Poké Portal on the X menu.
3. Select Mystery Gift, then select Get with Code/Password to connect to the internet.
4. Enter the password SH1NYBUDDY.
5. Watch as the gift arrives in your game. (Pokémon will appear in your party or your Pokémon Boxes.)
6. Be sure to save your game.

Notes:
• Passwords will never contain the letters I, O, or Z.
• You need to connect your Nintendo Switch system to the internet to claim this gift.
• To connect to the internet, your user profile must be linked to a Nintendo Account. (This does not require a paid Nintendo Switch Online membership.)
• This password can only be used once per save data.
• It takes approximately 1 to 1.5 hours of play time before you are able to access the Mystery Gift feature.

Source: https://sv-news.pokemon.co.jp/en/page/155.html