Urza, Lord Protector

While a melded permanent is on the battlefield, it has only the characteristics of its combined back face. Any effects that modify how the new object enters the battlefield will consider only the combined back face.

If an effect moves a melded permanent to a new zone and then affects "that card," it affects both cards.

Note that the permanent represented by the combined back faces has a color indicator.

Urza, Lord Protector's first ability can't reduce the colored mana costs of spells you cast.

When a pair of cards are melded, the result is a single creature that's represented by two cards. If the melded creature dies, both cards are put into your graveyard. As it leaves the battlefield, both of those cards are turned face up again. If the cards are put on the top or bottom of your library, you choose their relative order.

Only two cards belonging to the same meld pair can be melded. Tokens, cards that aren't meld cards, or meld cards that don't form a meld pair can't be melded. If an effect instructs a player to meld cards that can't be melded, those cards remain in exile.

One card in each pair of meld cards has an ability that instructs you to exile the two cards and meld them. If you control more than one object with one of those names, you select one object with that name to exile.

When two cards are exiled and melded, they each leave the battlefield, then return together as one new object with no relation to either of the objects that left the battlefield. Counters, Auras, Equipment, and other effects that affected those two cards don't affect the melded permanent.

While a meld card is in any zone other than the battlefield, it has only the characteristics of its front face. The same is true while it's on the battlefield with its front face up.