Invasion of Amonkhet // Lazotep Convert [March of the Machine]

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)

When Invasion of Amonkhet enters the battlefield, each player mills three cards, then each opponent discards a card and you draw a card. (To mill three cards, a plaver buts the top three cards of their library into their graveyard.)