[
    new MagicSpellCardEvent() {
        @Override
        public MagicEvent getEvent(final MagicCardOnStack cardOnStack,final MagicPayedCost payedCost) {
            final int amount=payedCost.getX();
            return new MagicEvent(
                cardOnStack,
                this,
                "Put "+amount+" -1/-1 counters on each creature. " + 
                "Shuffle SN into its owner's library."
            );
        }
        @Override
        public void executeEvent(final MagicGame game, final MagicEvent event) {
            final int amount = event.getCardOnStack().getX();
            final Collection<MagicPermanent> targets = 
                game.filterPermanents(event.getPlayer(),MagicTargetFilter.TARGET_CREATURE);
            for (final MagicPermanent target : targets) {
                game.doAction(new MagicChangeCountersAction(
                    target,
                    MagicCounterType.MinusOne,
                    amount,
                    true
                ));
            }
            game.doAction(new MagicChangeCardDestinationAction(event.getCardOnStack(),MagicLocationType.OwnersLibrary));
        }
    }
]