To lock half of a permanent, a player chooses an unlocked half of that permanent, and that permanent loses the appropriate unlocked designation
The Gen 4 Mythical is one of the set's only ten rare holographic cards

Take a look at the entire Commander deck below: Creatures (28) 1 Solemn Simulacrum 1 Hanna, Ship's Navigator 1 Vedalken Engineer 1 Silver Myr 1 Gold Myr 1 Etherium Sculptor 1 Master of Etherium 1 Indomitable Archangel 1 Myrsmith 1 Riddlesmith 1 Shimmer Myr 1 Whirler Rogue 1 Cataclysmic Gearhulk 1 Foundry Inspector 1 Sram, Senior Edificer 1 Aeronaut Admiral 1 Teshar, Ancestor's Apostle 1 Raff Capashen, Ship's Mage 1 Sai, Master Thopterist 1 Arcanist's Owl 1 Emry, Lurker of the Loch 1 Kotori, Pilot Prodigy 1 Research Thief 1 Katsumasa, the Animator 1 Kappa Cannoneer 1 Cyberdrive Awakener 1 Drumbellower 1 Ironsoul Enforcer Planeswalkers (1) Lands (37) Spells (34) 1 Swords to Plowshares 1 Sol Ring 1 Fellwar Stone 1 Thoughtcast 1 Azorius Signet 1 Dispatch 1 Reality Shift 1 Thopter Spy Network 1 Skysovereign, Consul Flagship 1 Smuggler's Copter 1 Cultivator's Caravan 1 Peacewalker Colossus 1 Mirage Mirror 1 Weatherlight 1 Crush Contraband 1 Parhelion II 1 Generous Gift 1 Arcane Signet 1 Dance of the Manse 1 Armed and Armored 1 Raiders' Karve 1 Colossal Plow 1 Surgehacker Mech 1 Prodigy's Prototype 1 Mobilizer Mech 1 Imperial Recovery Unit 1 Organic Extinction 1 Aerial Surveyor 1 Universal Surveillance 1 Shorikai, Genesis Engine 1 Imposter Mech 1 Access Denied 1 Swift Reconfiguration 1 Release to Memory What do you think of the Power Up deck and Shorikai, Genesis Engine

In game, the card allows the player to sacrifice the card when it is in play to generate three managame resources used to cast spells (play cards from the hand)
Why does Gastly seem okay with it, and why is Meowth eagerly watching from the sidelines