Exael of the Profane Soul

Menace
Whenever Exael of the Profane Soul deals
combat damage to a player, the next instant or
sorcery spell you cast this turn costs {x} less to
cast, where X is the damage dealt to that player
Pay 2 life, discard a card: Exael of the Profane
Soul gains +X/+0, where X is the discarded
card's converted mana cost.