gigantamax gengar pokemon card Pokémon GO – TRADE (Read Describe) Included in an acrylic case for lasting preservation and featuring a striking image of the captivating character Gigantamax Gengar (Pokémon GO) |

It provides immense flexibility because it hits multiple useful card types, and even if you mull down to 1 you're still seeing more cards than an opponent who has taken 0 mulligans

Sadly, this isnt a great payoff for a 9-mana investment that, to begin with, requires your opponents to have targetable creatures for you to tap down

Trades can only be done if both Pokmon TCG Pocket Cards are the same rarity, and only certain types of rarity can be swapped at the moment: One-Diamond to One-Star Cards

Your eighth colorless card doesnt directly add to your seventh the way Allies does

If that's an unsatisfying answer as to where Stax came from, maybe I can better explain why people play it