Aetherwind Basker (AER) from Aether Revolt, available at 401 Games Canada.

• Rarity: Mythic Rare
• Finish: Normal
• Artist: Svetlin Velinov
• Card Text:
  Trample
  Whenever Aetherwind Basker enters the battlefield or attacks, you get E (an energy counter) for each creature you control.
  Pay E: Aetherwind Basker gets +1/+1 until end of turn.