Sentry of Cradle's Shores

Defender, Spontaneous 2 (This creature enters
the battlefield with two +1/+1 counters on it. At
the beginning of your end step, remove a +1/+1 counter from this creature if able.)
Other creatures you control cannot have
+1/+1 counters removed from them if it is
the last +1/+1 counter on that creature.