At the beginning of your end step, for each player, put a +1/+1 counter on up to one target creature that player controls.
Each creature with one or more counters on it can't attack you or planeswalkers you control unless its controller pays {X}, where X is the number of counters on that creature.
Format Legality
Standard Not_legal
Pioneer Not_legal
Modern Not_legal
Legacy Legal
Vintage Legal
Commander Legal
Pauper Not_legal