Sickening Shoal (BOK) from Betrayers of Kamigawa, available at 401 Games Canada.

• Rarity: Rare
• Finish: Normal
• Artist: Dan Murayama Scott
• Card Text:
  You may exile a black card with converted mana cost X from your hand rather than pay Sickening Shoal's mana cost.
  Target creature gets -X/-X until end of turn.