Bounty Collector

When Bounty Collector enters the battlefield, you may put a Crime Counter onto a creature an opponent controls.(Creatures with Crime Counters have "When this creature dies, each opponent draws a card and gains 2 life." for each crime counter)
Whenever Bounty Collector is blocks or becomes blocked, those creatures get -X/-X until end of turn, where X is the total number of Crime Counters on those creatures.