Thornmantle Striker - Theme Booster (KHM) from Kaldheim, available at 401 Games Canada.

• Rarity: Uncommon
• Finish: Normal
• Artist: Magali Villeneuve
• Card Text:
  When Thornmantle Striker enters the battlefield, choose one —
  • Remove X counters from target permanent, where X is the number of Elves you control.
  • Target creature an opponent controls gets -X/-X until end of turn, where X is the number of Elves you control.