magarena/release/Magarena/scripts/Geistcatcher_s_Rig.groovy

[
    new MagicWhenComesIntoPlayTrigger() {
        @Override
        public MagicEvent executeTrigger(final MagicGame game,final MagicPermanent permanent, final MagicPayedCost payedCost) {
            return new MagicEvent(
                permanent,
                new MagicMayChoice(MagicTargetChoice.NEG_TARGET_CREATURE_WITH_FLYING),
                new MagicDamageTargetPicker(4),
                this,
                "PN may\$ have SN deal 4 damage " +
                "to target creature\$ with flying."
            );
        }
        @Override
        public void executeEvent(final MagicGame game, final MagicEvent event) {
            if (event.isYes()) {
                event.processTargetPermanent(game, {
                    final MagicPermanent creature ->
                    final MagicDamage damage = new MagicDamage(event.getPermanent(),creature,4);
                    game.doAction(new MagicDealDamageAction(damage));
                });
            }
        }
    }
]