Emrakul's Messenger Not sure you want to accept a message from Emrakul
While it can realistically be any card, Force of Negation is a decent fit
His ultimate, which costs 12 counters , is effectively a board wipe and can lead to a swift victory though do make sure you can swing for lethal before activating it
Unless that creature leaves combat, it continues to be a blocking creature through the end of combat step, even if the creature or creatures that it was blocking are no longer on the battlefield or have otherwise left combat by then
2024-02-02 The mana value of a spell cast without paying its mana cost is determined by its mana cost, even though that cost wasn't paid
which states, if you would flip a coin, instead flip two coins and ignore one. Such a wonderful way to win a game, flipping a coin all the way