Thresh, The Chain Warden

{b}{t}: Tap target creature an opponent controls.
At the beginning of your next upkeep, if Thresh
has a higher power than the target creature's toughness, exile that creature and give Thresh a
+1/+3 as long as that creature remains in exile.
At the beginning of your end step, if Thresh
hasn't attacked, give it a +1/+0. If Thresh has attacked, remove all +1/+0 counters gained this
way.