The Mewtwo ex in question here is another version of that same card, with the same effects. The difference is a cosmetic one: this Mewtwo ex is a "shiny", so it's green instead of pinkish, and has ...

Pokémon Trading Card Game Pocket players have, poetically, discovered Mew ex to be the perfect counter to Mewtwo ex, and one that can be slotted into every deck.