name: Heavy Fog
originalText: Play Heavy Fog only after you're attacked, before you declare blockers.
  This turn, all damage dealt to you by attacking creatures is reduced to 0.
printings: ME3, PTK
text: Cast this spell only during the declare attackers step and only if you've been attacked this step.
  Prevent all damage that would be dealt to you this turn by attacking creatures.
type: Instant