What is the name of the battle phenomenon introduced in Pokémon Scarlet and Violet?

Terastallization is the battle phenomenon introduced in Pokémon Scarlet and Violet.

During Terastallization, a Pokémon changes into a crystalline form and gains a Tera Type. Its Tera Type can alter its offensive and defensive matchups, and moves matching that type can receive a power boost. The mechanic is represented visually by a jewel-like crown above the Pokémon.

Scarlet and Violet were released for Nintendo Switch in November 2022 and take place in the Paldea region. The games also introduced an open-world structure, letting players approach three major story paths in a flexible order. Tera Raid Battles allow players to cooperate against especially powerful Terastallized Pokémon.

Terastallization belongs to a sequence of generation-specific battle mechanics. Mega Evolution debuted in Pokémon X and Y, Z-Moves in Sun and Moon, and Dynamax and Gigantamax in Sword and Shield. These systems are not interchangeable, even though each temporarily changes the potential of Pokémon during battles. Terastallization is specifically associated with Generation IX and the Paldea games.