Duskfield Grenade

All creatures on opponent's battlefield have a
-1/-1 slowed counter, which lasts for two turns
and negates haste.
{2}{u}{u}{b}{b}{t}: Replace slowed counter with a
frozen counter, which also lasts two turns.
A grenade that shatters on impact, leaving behind a
field that slows targets and freezes those who do not
leave the volume.