Scion of the Ur Dragon EDH

Dragon EDH with combos and such. COMBO 1: have Scion of the Ur Dragon on field and at least 4 mana of field. Pay 2 to have Scion become a copy of Skithiryx, the Blight Dragon. Then during damage phase after blockers are declared on the stack pay 2 more mana to have it become Moltensteel Dragon and pay either 1 mountain or 2 life to use Moltensteel Dragons effect to buff Scion by +1/+0. You will need to pay 12 life to buff Scion by +6/+0 if you lack mountains to pay. This will buff Scions attack making it a 10/4 with infect damage. If you have Bow of Nylea on feild use it to shuffle combo pieces back into deck then rinse and repeat. COMBO 2: have Scion of the Ur Dragon on field and at least 5 mana of field one of which needs to be a forest. Have Scion become a copy of Vorosh, the Hunter during combat phase, when it deals combat damage pay 2 mana and 1 forest to give Scion 6 +1/+1 counters on it. Next turn have it become copy of Dragon Tyrant and swing for 21 commander damage, if you have Bow of Nylea on field recycle combo pieces back into deck and repeat. COMBO 3: have Scion of the Ur Dragon on field and have it become a copy of Hellkite Charger or Hellkite Charger itself on field and at least 7 mana of field 2 of which need to be Mountains. Either equip Bear Umbra or Sword of Feast and Famine to either creatures both of which will untap your lands during combat phase. After lands are untapped pay the 7 mana on Hellkite Chargers effect giving you an extra combat phase. This will give infinite attacks until all opponents are dead. Other cards are shenanigans and support