Hars, the Fallen Life

Trample, Hexproof
{b}{g}{g}{t} Sacrifice another creature. Put X +1+1 counters on Hars, the Fallen Life, where X is that creature's power plus its toughness.
{g}{t} Return target creature from your graveyard
to the battlefield. Remove X +1+1 counters from
Hars, the Fallen Life, where X is that creature's
converted mana cost. You lose two life.