Argoth, Sanctum of Nature

You can activate the ability multiple times targeting the same land to add more counters.

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

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.

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.

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.

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.

In the Commander variant, a meld card's color identity is determined only by the mana costs and mana symbols in the rules text of its front face. No symbols or rules text of the permanent it melds into are considered.

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