It is card 14 of the 132 in the official Gym Challenge checklist. If you are completing the set, mark it in your collection to keep track.
Rarity: Holo Rare. The symbol in the bottom corner confirms it at a glance, as explained in Pokémon card rarities explained.
It exists in several finishes (Holo, 1st edition). Each one has its own price; the average above is for the regular version.
Artwork by Shin-ichi Yoshida. Some collectors chase every card by the same artist: how to start (in Spanish).
Attacks
Psychic
Juxtapose
Flip a coin. If heads, switch the number of damage counters on Rocket's Mewtwo with the number of damage counters on the Defending Pokémon (even if it would Knock Out either Pokémon). (It's okay if 1 of the Pokémon has no damage counters on it.)
PsychicPsychic
Hypnoblast
20
Flip a coin. If heads, the Defending Pokémon is now Asleep.