Zoetic Cavern (FUT) from Future Sight, available at 401 Games Canada.

• Rarity: Uncommon
• Finish: Normal
• Artist: Lars Grant-West
• Card Text:
  T: Add 1 to your mana pool.
  Morph 2 (You may play this face down as a 2/2 creature for 3. Turn it face up any time for its morph cost.)