
Flying
Whenever this creature attacks, you may pay . If you do, it deals X damage to any target.
He marks his territory with fire and wrath, etching the mountainside with his charring breath.
Illustrated by Jaime Jones · Magic 2012 · #133
2008-10-01
You choose the target when the ability triggers. When the ability resolves, you choose a value for X and decide whether to pay {X}{R}. If you do decide to pay {X}{R}, it's too late for any player to respond since the ability is already in the midst of resolving.