Chaeska, Keeper of Tresserhorn

Whenever a creature you control dies you may
pay {b} equal to its converted mana cost. If you do, exile that creature, then you may return another target creature with converted mana cost equal to or less than the amount of {b} you payed from a graveyard onto the battlefield under your control.
Pay 1 life: Add {b} to your mana pool. You may only use this effect three times each turn.