Double Star Card
From the Super Mario Wiki, the Mario encyclopedia
The Double Star Card is an item that is exclusive to the Balloon Bash mode of Mario Party: Star Rush. Obtained by landing on a ? Block when players are in lower positions or by purchasing them for 5 coins in Shy Guy Shops, these items double the amount of Stars earned when players visit Star Balloons. However, players have to pay for the extra Stars earned, meaning if that they cannot afford twice the amount, they can purchase more Stars only if their funds allow it. The Double Star Card is stackable, meaning that players can earn up to 12 Stars for 120 coins if used at a triple Star Balloon. Its Toad Scramble counterpart is the Double Card.