Heavy Fog | Magic: The Gathering
Formats Heavy Fog is Legal in
Official Oracle Text for Heavy Fog
Prevent all damage that would be dealt to you this turn by attacking creatures.
Official Rulings for Heavy Fog
10/1/2009 : Heavy Fog prevents only damage that would be dealt to you by attacking creatures. It won't prevent damage attacking creatures would deal to creatures or planeswalkers you control.
10/1/2009 : Heavy Fog prevents all damage attacking creatures would deal to you this turn, not just combat damage. Noncombat damage from those creatures is prevented only if they're still attacking at the time that damage would be dealt or, if the creature has left the battlefield by then, if it was an attacking creature at the time it left.