The Covetous

As an additional casting cost when casting any spell, you may pay 2 life. If you do, that spell costs {1} less. This effect reduces only the amount of generic mana that you pay.

Whenever you pay life as part of casting a spell or activating an ability exile the top card of target player's library face down. You may look at and play that card for as long as it remains exiled, and mana of any type may be used to cast that spell.