Autonomous Assembler (BRO) from The Brothers' War, available at 401 Games Canada.

• Rarity: Rare
• Finish: Normal
• Artist: Slawomir Maniak
• Card Text:
  Prototype (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.) 1W | 2/2
  Vigilance
  1, T: Put a +1/+1 counter on target Assembly-Worker you control.