Mewtwo Lv X is an interesting, if ultimately unfulfilling, card. 120 HP for a Basic Lv X is great, x2 Weakness to Psychic is...ok...no Resistance, and 2 Energy for a Retreat Cost is a bit expensive. Its Poke-Body, Psybarrier, is the main reason you will want to run this card; it prevents all Basic Pokemon from damaging Mewtwo, single-handedly stopping most AMU decks, as their Pokemon are all basic. However, it does leave something to be desired attack-wise; Giga Burn does an impressive 120 damage for 2 Psychic and 1 Colorless Energy, but it also requires you to discard all energy attached to Mewtwo. Though you have the regular Mewtwo to rely on as well