Kaya's Onslaught [Kaldheim] Shapeshifter Spirit Once you have been marked

Once you have been marked by the merrow

it deals double that damage to that player or permanent instead

if you have the initiative

You choose from it a nonland card with converted mana cost 3 or less and a card with converted mana cost 4 or greater

"We will defend the Worldsoul from Izzet 'progress' at any cost

Kaya's Onslaught [Kaldheim] Shapeshifter Spirit Once you have been markedSet: Kaldheim Type: Instant Rarity: Uncommon Cost: {2}{W} Target creature gets +1 +1 and gains double strike until end of turn. Foretell {W} (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.) "Your trail ends here."