Rot scavenger

{g};Exile a creature or land card from your graveyard: Put a +1/+1 counter on Rot scavenger
{1}{g}; exile target creature card from target opponent's graveyard : gain 2 life
{3}{g}; exile 3 cards from your graveyard: draw a card
{x}{g}: exile X cards from your graveyard: creatures you control get +X/+X until the end of turn