King's Hopeless Scream (CST-087 SR) [Clash of the Star Trees]

Draw two cards. J/resonators your opponent controls gain [-800/-800] until end of turn. [Seal] (X), where X is ten minus the number of Seven Kings rulers you own revealed outside the game. (As you play this card, if you control X or more magic stones, this card is played with the following text, where X is ten minus the number of Seven Kings rulers you own revealed outside the game.) You pay 0 rather than pay this card's cost if this is the first spell named "King's Hopeless Scream" you play this turn. Look at your opponent's hand and choose a card from among them. They discard the chosen card.