Permafrost Trap is a uncommon Instant — Trap card from Worldwake (WWK), collector number 34. Current market price: $0.15 (foil $0.40), TCGplayer market prices via Scryfall.
If an opponent had a green creature enter the battlefield under their control this turn, you may pay {U} rather than pay this spell's mana cost. Tap up to two target creatures. Those creatures don't untap during their controller's next untap step.