How does Terastallization change Pokémon battles?

Read the Tera Type, not the original silhouette

A Pokémon’s Tera Type can differ from its ordinary type or types. When it Terastallizes under the usual rules, incoming type matchups are evaluated against that Tera Type. A familiar weakness can disappear and a new one can take its place.

That can rescue a difficult matchup, but it can also expose a weakness your original typing resisted. Plan around what the opponent can actually use, not just the one attack you hope to avoid.

The attacking bonus is a separate layer

Terastallization preserves same-type bonuses associated with the Pokémon’s original typing while adding the relevant Tera interaction. Matching the Tera Type to an original type can strengthen that relationship. Specific Tera mechanics and exceptions need their own rules checked.

The ordinary type checker shows the type chart, not a complete Tera damage simulation. Use it to compare the defending Tera Type, then consider STAB and the other parts of the battle separately.

Use it with a concrete goal

Good reasons include surviving a predictable hit, strengthening the move needed to finish a fight, or supporting a planned raid role. Activating it immediately every battle can waste its tactical value.

Check the Tera Orb’s availability and recharge requirements in the current situation. Do not assume a previous fight leaves the resource ready for the next important encounter.

Raid bosses require two checks

A raid boss’s Tera Type tells you about its defensive weakness, while its species and moves help tell you what attacks your team must survive. Choosing only a move that is strong against the Tera icon can leave you vulnerable to the boss’s ordinary coverage.

Before committing resources to a build, decide whether it is intended for story battles, raids or a competitive format. Those goals can call for different Tera Types on the same species.