Aetherflux Reservoir (KLD) from Kaladesh, available at 401 Games Canada.

• Rarity: Rare
• Finish: Normal
• Artist: Cliff Childs
• Card Text:
  Whenever you cast a spell, you gain 1 life for each spell you've cast this turn.
  Pay 50 life: Aetherflux Reservoir deals 50 damage to target creature or player.