Saraab, Insidious Clergyman

When Saraab, Insidious Clergyman enters the battlefield, put a +1/+1 counter on all of your creatures for every creature target opponent
controls.
When Saraab, Insidious Clergyman leaves the battlefield, put a -1/-1 counter on all of target opponent's creatures for every creature you
control.
{b}{w}, Sacrifice 5 treasure tokens: Return Saraab, Insidious Clergyman to your hand.