magarena/release/Magarena/scripts/Cumber_Stone.groovy

[
    new MagicStatic(
        MagicLayer.ModPT, 
        MagicTargetFilter.TARGET_CREATURE_YOUR_OPPONENT_CONTROLS) {
        @Override
        public void modPowerToughness(final MagicPermanent source,final MagicPermanent permanent,final MagicPowerToughness pt) {
            pt.add(-1,0);
        }
    }
]