Massacre Girl, Known Killer - 94 M MKM

Menace
Creatures you control have wither. (They deal damage to creatures in the form of -1/-1 counters.)
Whenever a creature an opponent controls dies, if its toughness was less than 1, draw a card.
"'Did I do it?' You'll have to be more specific."
mythic
Legendary Creature — Human Assassin
From the Magic: The Gathering set Murders at Karlov Manor.