Barricade Breaker (AER) from Aether Revolt, available at 401 Games Canada.

• Rarity: Uncommon
• Finish: Normal
• Artist: Karl Kopinski
• Card Text:
  Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for 1.)
  Barricade Breaker attacks each combat if able.