Mogui, Embodiment of Pacts

Beguile {3}{b}{b}
If Mogui, Embodiment of Pacts is attached to a player, it gains "Enchanted player may cast spells from his or her hand without paying their mana cost. If they do, they loose life equal to half the spell's converted mana cost, rounded up. If enchanted player casts a spell without paying its mana cost, at the beginning of their next upkeep, they must pay that card's mana cost. If they don't, they lose the game."