Defiler of Vigor
Creature - Phyrexian Wurm | Power/Toughness: 6 / 6 (CMC 5)
As an additional cost to cast green permanent spells, you may pay 2 life. Those spells cost less to cast if you paid life this way. This effect reduces only the amount of green mana you pay.
Whenever you cast a green permanent spell, put a +1/+1 counter on each creature you control.