If you're playing Pokémon Scarlet and Violet and you're looking to evolve Basculin into Basculegion, we have the steps for you! Basculegion is a special evolution of White-Striped Basculin. Here's how you can accomplish this evolution and add Basculegion to your team.
First, you'll need to find a White-Striped Basculin. In Pokémon Scarlet and Violet, you can find White-Striped Basculin in The Timeless Woods located in Kitakami. The level of the Basculin you encounter may vary depending on your progress in the base game.
Once you have a White-Striped Basculin, you'll need to evolve it by having it take recoil damage without fainting. The evolution method is the same as in Pokémon Legends: Arceus. Your Basculin needs to take 294 damage or more from recoil damage. You can use moves such as Take Down, Wave Crash, or Double-Edge, which cause recoil, to accomplish this.
We recommend taking your Basculin to an area with Pokémon that are roughly 20 to 30 levels below it. This will ensure that your Basculin can survive the recoil damage and continue to battle. Keep track of the recoil damage your Basculin has taken by using a notepad or a digital app.
Once you have dealt enough recoil damage to your Basculin, all you need to do is level it up to evolve it into Basculegion. You can level up your Basculin either through normal battles or by using rare candies.
When your Basculin successfully evolves into Basculegion, its appearance will change. Basculegion will have red details if it's male and yellow with light blue details if it's female.
Now you're ready to have Basculegion join your Pokémon team in Pokémon Scarlet and Violet: The Teal Mask DLC. Good luck on your evolutionary journey!
Source: Pokémon Scarlet and Violet: The Teal Mask DLC, Game Freak and The Pokémon Company, Nintendo via Polygon.