Fall of the Impostor

When Valki enters, each opponent reveals their hand. For each opponent, exile a creature card they revealed this way until Valki leaves the battlefield. X: Choose a creature card exiled with Valki with mana value X. Valki becomes a copy of that card.

Whenever this creature attacks, you may sacrifice another creature. When you do, this creature deals damage equal to the sacrificed creature's power to any target. If the sacrificed creature was a Giant, this creature deals twice that much damage instead.

Scry X, where X is the amount of S spent to cast this spell, then draw three cards. (S is mana from a snow source.)

Return target creature card from your graveyard to the battlefield. If it's an Elf, create two 1/1 green Elf Warrior creature tokens. Foretell 3B (During your turn, you may pay 2 and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Exile target artifact, creature, or enchantment an opponent controls. That player may put a permanent card from their hand onto the battlefield.

Flying, haste Whenever this creature attacks or becomes the target of a spell, create a Treasure token. Treasures you control have "T, Sacrifice this artifact: Add two mana of any one color."

Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.

Enchant land Enchanted land is snow. Whenever enchanted land is tapped for mana, its controller adds an additional one mana of any color.