Obscuring Haze 
Instant
If you control a commander, you may cast this spell without paying its mana cost. Prevent all damage that would be dealt this turn by creatures your opponents control.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL