Massacre Girl, Most Wanted is a uncommon Legendary Creature — Human Assassin card from Reality Fracture (FRA), collector number 234. Current market price: $0.23 (foil $0.36), TCGplayer market prices via Scryfall.
Whenever another creature or planeswalker you control dies, Massacre Girl deals 1 damage to target opponent and you gain 1 life. Whenever an opponent is dealt noncombat damage, put a +1/+1 counter on Massacre Girl.