Serpanto, King of the Critters

Deathtouch, Menace, Hexproof
At the beginning of your upkeep, mill three cards and then put two creature, artifact, and/or enchantments onto the battlefield from the graveyard. Target opponent loses 2 life for each permanent that entered the battlefield this way.
Whenever an opponent loses life, you may add {b}{b} to your mana pool and you gain 2 life.