Lupilis, the Grave Spirit

Whenever a creature you control dies put a +1/+1 counter on Lupilis, the Grave Spirit.
Remove X +1/+1 counters: Return target creature from your graveyard to the battlefield, with converted mana cost equal to the number of +1/+1 counters removed this way. You may activate this ability only once each turn.
"He protects all spirits; even the downright cruel."