Emrakul, Herald of Fealty

Flying, trample, protection from colored spells.
Whenever Emrakul, Herald of Fealty attacks, gain control of target permanent for as long as you control Emrakul, Herald of Fealty.
Whenever Emrakul, Herald of Fealty deals combat damage to a player, gain control of that player for as long as you control Emrakul, Herald of Fealty. Then, if you control all players, you win the game.