magarena/release/Magarena/scripts/Unsummon.groovy

[
    new MagicSpellCardEvent() {
        @Override
        public MagicEvent getEvent(final MagicCardOnStack cardOnStack,final MagicPayedCost payedCost) {
            return new MagicEvent(
                cardOnStack,
                MagicTargetChoice.TARGET_CREATURE,
                MagicBounceTargetPicker.getInstance(),
                this,
                "Return target creature\$ to its owner's hand."
            );
        }
        @Override
        public void executeEvent(final MagicGame game, final MagicEvent event) {
            event.processTargetPermanent(game,new MagicPermanentAction() {
                public void doAction(final MagicPermanent creature) {
                    game.doAction(new MagicRemoveFromPlayAction(creature,MagicLocationType.OwnersHand));
                }
            });
        }
    }
]