magarena/release/Magarena/scripts/Grounded.groovy

[
    new MagicStatic(
        MagicLayer.Ability, 
        MagicTargetFilter.TARGET_CREATURE) {
        @Override
        public void modAbilityFlags(
                final MagicPermanent source,
                final MagicPermanent permanent,
                final Set<MagicAbility> flags) {
            flags.remove(MagicAbility.Flying);
        }
        @Override
        public boolean condition(
                final MagicGame game,
                final MagicPermanent source,
                final MagicPermanent target) {
            return target == source.getEnchantedCreature();
        }
    }
]