Peaceful Watcher

When Peaceful Watcher enters the battlefield,
Peace 1. (To peace 1, put 1 peace counter on
each creature target opponent controls. At the beginning of each opponent's end step, they
remove a peace counter from a creature he/she controls. Creatures with peace counters can't
attack or be dealt combat damage.)
{w}, Remove a Peace counter from a creature an opponent controls: You gain 3 life.