pokemon gen 4 booster box TCG: Chinese - Gem Vol [Booster Box] with 3 guaranteed foil cards per booster) Pokemon TCG S-Chinese CBB4C Gem

Beyond only creating colorless mana, this mana can only be spent on artifact spells

Its second attack, Obsidian, is incredibly useful against other Stage 2 decks, as it can knock them out before they get set up, making it an incredibly strong option in the current format

The utility of being able to use this as a (sorcery-speed) pump spell in addition to the fight mechanic was extremely valuable to those decks at the time, which were full of cards like Questing Beast, Lovestruck Beast, Gemrazer, Kazandu Mammoth and other beefy creatures that benefited heavily from fighting

Meaning Rillaboom can deal up to 280 damage