Commence the Offering

Whenever you cast Commence the Offering, if
you paid {p/b} with two life, draw two cards.
{b}{b}, Discard a card: Search your library for a card with converted mana cost equal to or less than the card you discarded this way.
{b}{b}{b}{b}, Sacrifice Commence the Offering: Destroy all non-black creatures. Target player loses life equal to the number of creatures destroyed this way.