this.color.setBlack(true);
this.power = new MageInt(0);
this.toughness = new MageInt(0);
// Festercreep enters the battlefield with a +1/+1 counter on it.
this.addAbility(new EntersBattlefieldAbility(new AddCountersSourceEffect(CounterType.P1P1.createInstance(1))));
// {1}{B}, Remove a +1/+1 counter from Festercreep: All other creatures get -1/-1 until end of turn.
Ability ability = new SimpleActivatedAbility(Zone.BATTLEFIELD, new BoostAllEffect(-1, -1, Duration.EndOfTurn, new FilterCreaturePermanent(), true), new ManaCostsImpl("{1}{B}"));
ability.addCost(new RemoveCountersSourceCost(CounterType.P1P1.createInstance(1)));
this.addAbility(ability);