Sarkhan, Dragon Ascendant 
Legendary Creature — Human Druid
When Sarkhan enters, you may behold a Dragon. If you do, create a Treasure token. (To behold a Dragon, choose a Dragon you control or reveal a Dragon card from your hand.) Whenever a Dragon you control enters, put a +1/+1 counter on Sarkhan. Until end of turn, Sarkhan becomes a Dragon in addition to its other types and gains flying.
Legality
standardLEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL