Permafrost Trap (WWK) from Worldwake, available at 401 Games Canada.

• Rarity: Uncommon
• Finish: Normal
• Artist: Howard Lyon
• Card Text:
  If an opponent had a green creature enter the battlefield under his or her control this turn, you may pay U rather than pay Permafrost Trap's mana cost.
  Tap up to two target creatures. Those creatures don't untap during their controller's next untap step.