// Whenever you cast a noncreature spell, you may pay {1}. If you do, tap target creature an opponent controls and it doesn't untap during its controller's next untap step.
DoIfCostPaid doIfCostPaid = new DoIfCostPaid(new TapTargetEffect(), new GenericManaCost(1),"Tap creature?");
Effect effect = new SkipNextUntapTargetEffect();
effect.setText("and it doesn't untap during its controller's next untap step");
doIfCostPaid.addEffect(effect);
Ability ability = new SpellCastControllerTriggeredAbility(doIfCostPaid, filterNonCreature, false);
ability.addTarget(new TargetCreaturePermanent(filter));
this.addAbility(ability);
}