Pokémon Horizons confirms that it's trying to be as faithful to the Pokémon games as possible, by having characters make use of the Paldea region's exclusive Terastal mechanic from Pokémon Scarlet and Violet, giving the new game gimmick its first anime appearances.
The transformation sequence in the anime was very close to how it looks in the games, and it actually came across as quite cool. In episode #10 of Pokémon Horizons, Gym Leader Brassius showcased Terastallization for the first time, using it on his Sudowoodo to beat Roy in his first Gym Battle. The mechanic then returns in episode #14, when Friede pulls out a Tera Orb, the device needed to utilize Terastallization, and declares that Charizard must surpass its limits, transferring the energy to it and causing it to become a Dark-type, which was particularly handy, as Friede was up against a Psychic-type, Beheeyem, being remotely commanded by the new villain Spinel. Friede takes advantage of Charizard's newfound immunity to Psychic-type attacks to retaliate, allowing him to escape the trap he'd fallen into.
Pokémon Horizons Impresses With Its Terastallizations
In the games, Terastallization is a mechanic which allows a Pokémon to change its type mid-battle, offering a myriad of strategic opportunities for tactically-minded trainers to make use of. The transformation is easily recognized by the Pokémon taking on a crystalline appearance, along with a somewhat goofy-looking "hat" that reveals what type the Pokémon has become. Scarlet and Violet came out a little too late for the mechanic to ever make an appearance in the anime under Ash, and due to it only working in the Paldea region, there was no real way for it to show up until the Horizons characters arrived there.
Things were looking pretty grim for Friede, as he was up against two Pokémon with just his one Charizard to work with. Had Friede not had the Tera Orb, the entire situation might've ended very differently, so the new mechanic really saved the day here by rendering Charizard immune to Psychic and removing its weakness to Electric attacks. The Tera Orb offered Friede an element of surprise that he needed to regain the upper hand as well. All in all, it was an excellent first appearance for the Tera transformation, and likely just one of many now that it's known that Friede has a Tera Orb at his disposal.
Pokémon Horizons Is Doing A Great Job At Adapting Scarlet And Violet
While Ash's adventures in the Pokémon anime only took loose inspiration from the games, it's clear that Horizons is committing to giving fans the most accurate adaptation of the Pokémon games possible. After Friede showcased his Tera Orb powers, the question remains if his Captain Pikachu is also capable of Terastallizing, which is surely something that fans would be excited to see. Pokémon Horizons has done a good job of showcasing the Paldea region and all that Scarlet and Violet have to offer, so it's little wonder that the series also managed to handle its new Terastal mechanic just fine.