Permafrost Trap
03b6dc43-62d3-4572-a2e1-b0e67dcc21c7
$0.50 CND
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.