Deeproot Waters (LCC) from The Lost Caverns of Ixalan Commander, available at 401 Games Canada.

• Rarity: Uncommon
• Finish: Normal
• Artist: Zezhou Chen
• Card Text:
  Whenever you cast a Merfolk spell, create a 1/1 blue Merfolk creature token with hexproof. (A creature with hexproof can't be the target of spells or abilities your opponents control.)