Chloe, Unsavory Fixer

Wither (This deals damage to creatures in the form
of -1/-1 counters.)
Whenever one or more -1/-1 counters are put on
a creature you don't control, choose one —
• Until end of turn, cards in your graveyard with
mana value less than or equal to the amount of counters placed have scavenge {2}{b}{g}.
• Exile up to that many cards from an opponent's graveyard.