Laxon, The Black Horse

{t} Laxon, The Black Horse, has a +2/+2 counter for each card in your graveyard.
{b/g}{b/g} Sacrifice a creature. Target player loses life equal to combined power and toughness.
{x}{b}{g} You gain X life and put X cards from your graveyard on the battlefield. Each opponent loses X life and sacrifices X permanents and discards the top X cards of their library.