Tribute

A keyword and card mechanic that may be manually procced on the turn a unit is played, with a Coin cost.

When a unit with Tribute is played, you will be given the option either to pay Tribute or not, and if you do, then the specified number of Coins will be deducted from your balance in order to proc the effect. This makes Tribute effects effectively like optional Deploy abilities with a cost, which are single-use and only trigger when a card is played, not Summoned.