Dr. Necris Phage

+3: Destroy target creature. Put a number of +1/+1 counters onto target creature equal to its toughness.
0: Until your next upkeep, Necris is a 6/6 green and black artifact creature with indestructible, hexproof, and deathtouch.
-12: Put a poison counter on each other player and a -1/-1 counter on each creature. Proliferate X times where X is your life total.