Unown M (Mysterious Treasures 66/123), Uncommon, Basic, 50 HP. Illustrated by Kazuyuki Kano. Prices are estimates from TCGPlayer and Cardmarket, not guaranteed values.
Shaped like ancient writing, it is a huge mystery whether language or UNOWN came first.
Card text
Poke-POWER: MAGNET — Once during your turn (before your attack), if Unown M is your Active Pokémon, you may flip a coin. If heads, switch 1 of your opponent's Benched Pokémon with 1 of the Defending Pokémon. This power can't be used if Unown M is affected by a Special Condition.
Hidden Power — Flip a coin. If heads, this attack does 30 damage. If tails, this attack does 30 damage to 1 of your Pokémon, and this attack's damage isn't affected by Weakness or Resistance.
Questions
Is Unown M 66/123 rare?
It is an Uncommon from Mysterious Treasures, a 123-card set.
Is Unown M 66/123 tournament legal?
Unown M 66/123 has rotated out of the current formats.