Mantra of Restraint

At the beginning of your end step, if no creatures
died as a result of combat damage this turn, put a
restraint counter on this card. Then put a +1/+1
counter on up to one creature you control.
Exile Mantra of Restraint: Target creature you
control gains +X/+X until end of turn, where
X is the amount of restraint counters on this
card.
"Control whets the claw. Calmness hones the fang."