Peacekeeper | Magic: The Gathering
Formats Peacekeeper is Legal in
Official Oracle Text for Peacekeeper
Creatures can't attack.
Official Rulings for Peacekeeper
4/1/2008 : If the creature is no longer on the battlefield when the ability resolves, you may still perform the action if you want.
4/1/2008 : Peacekeeper's ability doesn't cause the combat phase or the declare attackers step to be skipped.