Flying
When this creature enters, you may pay {2}{R}. When you do, it deals 3 damage to any target.
You don't choose a target for Sparktongue Dragon's last ability at the time it triggers. Rather, a second "reflexive" ability triggers when you pay {2}{R} this way. You choose a target for that ability as it goes on the stack. Each player may respond to this triggered ability as normal.