this.color.setBlack(true);
this.power = new MageInt(0);
this.toughness = new MageInt(0);
// Pack Rat's power and toughness are each equal to the number of Rats you control.
this.addAbility(new SimpleStaticAbility(Zone.ALL, new SetPowerToughnessSourceEffect(new PermanentsOnBattlefieldCount(filter), Duration.EndOfGame)));
// {2}{B}, Discard a card: Put a token onto the battlefield that's a copy of Pack Rat.
Ability ability = new SimpleActivatedAbility(Zone.BATTLEFIELD, new PackRatEffect(this), new ManaCostsImpl("{2}{B}"));
ability.addCost(new DiscardCardCost());
this.addAbility(ability);
}