Undertale’s Toby Fox is behind the overworld theme for Pokémon Scarlet and Violet

A few more Toby Fox tracks will appear in both versions of the game.

Image via The Pokemon Company

If any players were nodding to the beat of the music in the newest Pokémon Scarlet and Violet trailer, we might know why now — Undertale creator Toby Fox contributed to the game’s soundtrack. Fox revealed in a tweet that he composed “the field music” for Pokémon Scarlet and Violet. You can hear a bit of it in the trailer, though it isn’t clear which sections were composed by Fox. The composer added that his contribution to the upcoming titles has been arranged into different versions that players will hear throughout the game.

Related: Pokémon Scarlet and Violet’s second trailer reveals two professors, cooperative play, featured legendaries, and November release date

The Undertale creator added that “a few more Toby Fox tracks will appear in the game” and he hopes players look forward to it as “this time, my music is not optional” in a cheeky message. This isn’t the first time that Toby Fox has had a musical involvement with the Pokémon games — the game creator composed a track for Pokémon Sword and Pokémon Shield after composing the soundtrack for developer Game Freak’s game Little Town Hero.

Toby Fox’s journey to producing tracks for Pokémon games all started when he started designing EarthBound ROM hacks in RPG Maker when he was 16 years old. That led him to compose Homestuck music and later on create one of his most well-known projects to date with Undertale, thought to be one of the most influential games in recent years.

Nintendo released Pokémon Scarlet and Violet’s second trailer that revealed the November launch date of its upcoming open-world Pokémon titles, alongside a bevy of details. Some of these include the game’s rival, both versions’ exclusive professors, multiplayer with up to four players, and new Pokémon alongside the reveal of the game’s title cover Legendaries.