Ahn-Crop Crasher (AKH) from Amonkhet, available at 401 Games Canada.

• Rarity: Uncommon
• Finish: Normal
• Artist: Seb McKinnon
• Card Text:
  Haste
  You may exert Ahn-Crop Crasher as it attacks. When you do, target creature can't block this turn. (An exerted creature won't untap during your next untap step.)