Aurification (ONS) from Onslaught, available at 401 Games Canada.

• Rarity: Rare
• Finish: Normal
• Artist: Gary Ruddell
• Card Text:
  Whenever a creature deals damage to you, put a gold counter on it.
  Each creature with a gold counter on it is a Wall in addition to its other creature types. (Walls can't attack.)
  When Aurification leaves play, remove all gold counters from all creatures.