All creatures get -1/-0 until end of turn.
The brightness of day turned in an instant to dusk as the swarm descended upon the battlefield.
Illustrated by Christopher Rush · Legends · #103
There are no rulings for Hell Swarm.
All creatures get -2/-0 until end of turn.
All creatures get -1/-1 until end of turn.
Target creature gets +2/-2 until end of turn.
Target creature gets -3/-1 until end of turn.
Target creature gets -2/-2 until end of turn.