AttackPhoton Wave
During your opponent's next turn, any damage done by attacks from the Defending Pokémon is reduced by 30 (before applying Weakness and Resistance).

Mewtwo is Pokédex #150, generation 1 (Kanto). Mewtwo-EX is a Basic EX Psychic Pokémon with 170 HP. The card lists M Mewtwo-EX, Mewtwo (#150) under evolves to.
Mewtwo-EX sits at XY125/211 in XY Black Star Promos, position 126 of 216. Before it is XY124 Pikachu-EX, and after it is XY126 Mew-EX. The set belongs to the XY series. It was released on 12 October 2013. The printed size is 211. This checklist is longer, at 216 cards. The listed rarity is Promo.
The attack Photon Wave lists 30 damage. The cost is Colorless, Colorless. During your opponent's next turn, any damage done by attacks from the Defending Pokémon is reduced by 30 (before applying Weakness and Resistance). Psyburn is another attack lists 120 damage. The cost is Psychic, Psychic, Colorless, Colorless. Weakness is Psychic ×2. Retreat cost is 2. The card text says: Pokémon-EX rule: When a Pokémon-EX has been Knocked Out, your opponent takes 2 Prize cards.
Mewtwo (#150) has 88 other cards in the catalog. Those other cards are in 42 sets. The other printings with a release date run from 1999 to 2026. The earliest other card is Mewtwo 10/102 in Base (1999). That card is named Mewtwo, while this one is Mewtwo-EX. That card lists 60 HP, and this one lists 170 HP. The rarity there is Rare Holo, and here it is Promo. Ken Sugimori illustrated that card, and Eske Yoshinob illustrated this one. Retreat cost there is 3, and here it is 2. 75 other cards of Mewtwo list a different HP.
The illustrator line reads Eske Yoshinob. I count 177 other cards in the catalog with that illustrator.
XY Black Star Promos set binder is where a full XY Black Star Promos set goes. This card fills one slot there. A generation binder holds one card of each species. Mewtwo can fill a slot in Generation 1 binder (Kanto). Themed lists that include this exact card are Mew and Mewtwo. I still need this card.
During your opponent's next turn, any damage done by attacks from the Defending Pokémon is reduced by 30 (before applying Weakness and Resistance).
Pokémon-EX rule: When a Pokémon-EX has been Knocked Out, your opponent takes 2 Prize cards.
XY Black Star Promos, in the XY series. It was released on 12 October 2013. The printed size is 211.
XY125/211. It is entry 126 of 216 in this checklist.
Eske Yoshinob. The catalog lists 177 other cards with that illustrator.
Promo.
Mewtwo #150, generation 1 (Kanto).
Photon Wave (30) and Psyburn (120).