Raffine's Silencer 

Creature — Human Assassin
When this creature enters, it connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.) When this creature dies, target creature an opponent controls gets -X/-X until end of turn, where X is this creature's power.
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL