Eldritch Moon mechanics

Prerelease of Eldritch Moon starts July, 16-17 and a dozen of new cards have been spoiled recently, meaning that new mechanics were revealed:

• Meld, a keyword action that changes the card with meld and a specific other card into one oversized card. That single card is printed on the backs of the two other cards. From now on, it is one pernament, so a single spell that says "Destroy target creature" takes out the whole. The differences kick in if it leaves the battlefield. Wherever that permanent goes, both cards go, and they each turn front face up again. 
• Emerge [cost] - You may cast this spell by sacrificing a creature and paying the emerge cost reduced by that creature's converted mana cost. The discount you get can't affect the colored mana part of the emerge cost.
• Escalate, a keyword ability appearing on modal instants and sorceries, which offers you a bulleted list of different effects. By paying the escalate cost, additional modes may be activated.