It is card 10 of the 132 in the official Gym Heroes 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 Ken Sugimori. Some collectors chase every card by the same artist: how to start (in Spanish).
Abilities
Flee Pokemon Power
If an attack does damage to Misty's Tentacruel while it's your Active Pokémon, you may switch it with 1 of your Benched Pokémon, which prevents all other effects of that attack on Misty's Tentacruel. This power can't be used if Misty's Tentacruel is already Asleep, Confused, or Paralyzed.
Attacks
WaterWaterColorlessColorless
Jellyfish Poison
Flip a coin. If heads, the Defending Pokémon is now Poisoned. If tails, the Defending Pokémon is now Confused.