Zerg Broodmother

Hive Commander - Other Zerg creatures you control get +1/+1.

Endless Brood - Whenever a nontoken Zerg you control dies, create two 1/1 black Zergling creature tokens.

Evolve the Swarm - {2}{b}{g}, Sacrifice a Zerg: Put two +1/+1 counters on Zerg Broodmother and draw a card.

"The hive never stops growing. The Swarm is infinite."