2008-08-01 : It doesn’t matter how many -1/-1 counters were on the creature when it was put into a graveyard from the battlefield, as long as it had at least one.

2008-08-01 : It doesn’t matter whose graveyard the creature is put into. It matters only that an opponent controlled it when it left the battlefield.

2008-08-01 : The card returns to the battlefield without any -1/-1 counters on it (unless some other effect causes it to enter the battlefield with some).