[
    new MagicWhenBecomesBlockedTrigger() {
        @Override
        public MagicEvent executeTrigger(final MagicGame game,final MagicPermanent permanent,final MagicPermanent blocked) {
            return (permanent == blocked) ?
                new MagicEvent(
                    permanent,
                    permanent.getOpponent(),
                    this,
                    "PN loses 4 life."
                ):
                MagicEvent.NONE;
        }
        
        @Override
        public void executeEvent(
                final MagicGame game,
                final MagicEvent event) {
            game.doAction(new MagicChangeLifeAction(event.getPlayer(),-4));
        }
    }
]