this.color.setGreen(true);
this.power = new MageInt(0);
this.toughness = new MageInt(0);
// Uktabi Wildcats's power and toughness are each equal to the number of Forests you control.
this.addAbility(new SimpleStaticAbility(Zone.ALL, new SetPowerToughnessSourceEffect(new PermanentsOnBattlefieldCount(filter), Duration.EndOfGame)));
// {G}, Sacrifice a Forest: Regenerate Uktabi Wildcats.
Ability ability = new SimpleActivatedAbility(Zone.BATTLEFIELD, new RegenerateSourceEffect(), new ManaCostsImpl("{G}"));
ability.addCost(new SacrificeTargetCost(new TargetControlledPermanent(1, 1, sacrificeFilter, true)));
this.addAbility(ability);