Jezebeth, the 'Generous'

On each player's upkeep that player may choose a card exiled with Kedron, Cruel Advisor and pay 'x' life, where x is the card's converted mana cost. That player may cast
the card from exile, spending mana as if it
was any color to cast the card.
Partner with Kedron, Cruel Advisor
You want it, it's going to cost you.