this.color.setGreen(true);
this.power = new MageInt(1);
this.toughness = new MageInt(1);
// Whenever a player casts a green spell, you may pay {1}. If you do, target creature gets +1/+1 until end of turn.
Ability ability = new SpellCastAllTriggeredAbility(new DoIfCostPaid(new BoostTargetEffect(1, 1, Duration.EndOfTurn), new ManaCostsImpl("{1}")), filter, false);
ability.addTarget(new TargetCreaturePermanent());
this.addAbility(ability);
}