Night Witch Exultia

Hexproof.
If a creature were to enter a graveyard from anywhere, create 1/1 Plague Rat token creatures with deathtouch, equal to that creature's toughness.
Sacrifice a creature: Creatures your opponents control get -1/-1 until end of turn. Put a +1/+1 counter on Night Witch Exultia for each creature that died this way.