A Basic, EX Pokemon Card of type Psychic with the title Mew ex and 90 HP of rarity Classic Collection from the set Celebrations: Classic Collection.  It has the attack Power Move with the cost Psychic, Colorless, the energy cost 2 with the description: Search your deck for an Energy card and attach it to Mew ex. Shuffle your deck afterward. Then, you may switch Mew ex with 1 of your Benched Pokemon. It has the ability Versatile with the description: Mew ex can use the attacks of all Pokemon in play as its own. (You still need the necessary Energy to use each attack.) It has weakness against Psychic 2. 
Mew ex