Phyrexian Drossfiend

Deathtouch

As an additional cost to cast a spell, its controller may pay 2 life up to once for each colored mana symbol in that spell’s mana cost. That spell costs {w}, {u}, {b}, {r}, or {g} less to cast for each time this cost was paid. This effect reduces only the amount of colored mana its controller pays.

Whenever a player loses life, you draw that many cards.