The Terastal Fest ex set marked a significant moment in Japanese Pokémon TCG history, introducing the Terastal mechanic that had recently debuted in the Scarlet and Violet video games. Released in 2024, this set captured collectors' attention with its showcase of Pokémon in their crystalline Terastal forms. The Master Ball Reverse Holo treatment became highly sought after during this period, offering a premium aesthetic that appealed to both competitive players and collectors pursuing complete set variants. Iron Boulder presents the steel and psychic-type legendary Pokémon with the striking visual treatment characteristic of Terastal artwork. Collectors are drawn to this card for its bold design and the rarity of the Master Ball Reverse Holo finish, which creates distinctive light-play effects across the card's surface. It represents a standout pull from an era when Japanese TCG production quality and artistic presentation reached new heights.