Lunete, the Icefallen

Flying
Whenever Lunete, the Icefallen deals combat damage to a player you may pay {2}{u}{u}. If you do, tap all creatures target opponent controls. They don't untap during that opponent's next untap step.
{6}{u}{u}{u}: Tap all creatures. They don't untap during the untap step. They gain '{3}: Untap this creature.'