Tainted Field (DDK) from Duel Decks: Sorin vs. Tibalt, available at 401 Games Canada.

• Rarity: Uncommon
• Finish: Normal
• Artist: Don Hazeltine
• Card Text:
  T: Add 1 to your mana pool.
  T: Add W or B to your mana pool. Activate this ability only if you control a Swamp.