Gyarados ex 225/198 (Scarlet & Violet)

Attacks

Waterfall (100):

Tyrannical Tail (180+): If your opponent's Active Pokémon already has any damage counters on it, this attack does 180 more damage.

Rules

Tera: As long as this Pokémon is on your Bench, prevent all damage done to this Pokémon by attacks (both yours and your opponent's).

Pokémon ex rule: When your Pokémon ex is Knocked Out, your opponent takes 2 Prize cards.