The Ur-Dragon is a mythic Legendary Creature — Dragon Avatar card from Treasure Chest (PZ2), collector number 65675.
Eminence — As long as The Ur-Dragon is in the command zone or on the battlefield, other Dragon spells you cast cost {1} less to cast. Flying Whenever one or more Dragons you control attack, draw that many cards, then you may put a permanent card from your hand onto the battlefield.