Which of You Burns Brightest?

When you set this scheme in motion, you may pay {X}. If you do, this scheme deals X damage to target opponent or planeswalker and each creature that player or that planeswalker's controller controls.

From Magic: The Gathering.

Open the interactive version on https://mythscribe.cloud/app/tcg/cards/cms6ohmpfcoedpb1h0yii0zxe.