Spreading Fatigue

When Spreading Fatigue enters the battlefield,
put a -1/-1 counter on up to one target creature.
At the beginning of your upkeep, for each
creature with a -1/-1 counter on it, put a -1/-1
counter on up to one target creature.
{x}{b}{b}, Sacrifice Spreading Fatigue: Put X -1/-1 counters on each creature.