The Great Unclean One

Infect
When this card enters the battlefield put
three counters -1/-1 in target creature
if any creature dies for this effect pass all
counters plus 1 to other creature
{t}{g}{g}{g}{g} put 1/3 green poxwalkers tokens
on the battlefield equal to the number of green creatures
in all players graveyards.
This card cost {g} less equal to the number of
cards with negative counters on it