Brood Pact

Whenever your opponents cast a spell, Creatures you control gain +0/+X until end of turn, where X is equal to the number of other creatures with the same subtype on your side of the field. Whenever an opponent draws a card, creatures you control gain hexproof until the end of the current phase.
"When you're at your peak of confidence against us, you've already lost."
-Sabin Vein.