Delve (Each card you exile from your graveyard while casting this spell pays for.)
Destroy target nongreen creature. It can't be regenerated.
6/7/2013 Delve reduces only the generic mana requirement of the spell.
6/7/2013 If you sacrifice permanents or discard cards while casting the spell (for example, activating the mana ability of Blood Pet), those cards can be exiled using delve to reduce the spell’s cost.