Demon of Fate's Design
From Duskmourn: House of Horror Commander set
Demon of Fate's Design
Enchantment Creature — Demon
6/6
Flying, trample
Once during each of your turns, you may cast an enchantment spell by paying life equal to its mana value rather than paying its mana cost.
, Sacrifice another enchantment: This creature gets +X/+0 until end of turn, where X is the sacrificed enchantment's mana value.