Dragonlord's Prerogative 
Instant
As an additional cost to cast this spell, you may reveal a Dragon card from your hand. If you revealed a Dragon card or controlled a Dragon as you cast this spell, this spell can't be countered. Draw four cards.
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL