Phantump and Trevenant are ghost- and grass-type Pokémon originally from the Kalos region, but now they’re part of Pokémon Scarlet and Violet: The Teal Mask DLC.
The spooky tree Pokémon can be found pretty commonly around Kitakami, but if you have one you specifically want to evolve, you’ll need to get help from other players. We detail how to find Phantump and evolve it below.
Where to find Phantump in Pokémon Scarlet and Violet
You can find Phantump in both the Timeless Woods and in the bamboo forest in Kitakami. It’s pretty common.
How to evolve Phantump into Trevenant
To evolve Phantump into Trevenant, you’ll need to trade the Phantump to another player. Upon arriving to the other player, it’ll evolve immediately.
To easily find other players looking to swap Phantumps for Trevenant evolutions, you can use the trade code “07080708,” created by YouTuber Austin John Plays. Note that using this code will trade your Phantump one way and the other trainer will likely disconnect, not allowing you to get your original Trevenant back. If you’re evolving a shiny Phantump or one with specific stats you want, you may want to just ask a friend.
Those without a Nintendo Switch Online subscription will have to trade with a friend locally to evolve their Phantump, but it is worth pointing out that you can just straight-up catch Trevenant in the wild. There are many roaming around the eastern side of Timeless Woods (or so we saw while exploring).