magarena/release/Magarena/scripts/Wall_of_Frost.groovy

[
    new MagicWhenBlocksTrigger() {
        @Override
        public MagicEvent executeTrigger(final MagicGame game,final MagicPermanent permanent,final MagicPermanent blocker) {
            final MagicPermanent blocked=permanent.getBlockedCreature();
            return (permanent==blocker && blocked.isValid()) ?
                new MagicEvent(
                    permanent,
                    blocked,
                    this,
                    "RN doesn't untap during its controller's next untap step."
                ):
                MagicEvent.NONE;
        }
        @Override
        public void executeEvent(
                final MagicGame game,
                final MagicEvent event) {
            game.doAction(new MagicChangeStateAction(event.getRefPermanent(),MagicPermanentState.DoesNotUntapDuringNext,true));
        }
    }
]