How to use

mage.abilities.effects.common.TransformTargetEffect

constructor

@Override
public TransformTargetEffect copy() {
  return new TransformTargetEffect(this);
}

@Override
public boolean apply(Game game, Ability source) {
  MageObject sourceObject = source.getSourceObjectIfItStillExists(game);
  if (sourceObject instanceof Permanent) {
    //create delayed triggered ability
    Effect effect = new TransformTargetEffect(false);
    effect.setTargetPointer(new FixedTarget((Permanent) sourceObject, game));
    AtTheBeginOfNextUpkeepDelayedTriggeredAbility delayedAbility = new AtTheBeginOfNextUpkeepDelayedTriggeredAbility(effect);
    game.addDelayedTriggeredAbility(delayedAbility, source);
  }
  return true;
}

public WaxingMoon(UUID ownerId, CardSetInfo setInfo) {
  super(ownerId,setInfo,new CardType[]{CardType.INSTANT},"{1}{G}");
  // Transform up to one target Werewolf you control.
  Effect effect = new TransformTargetEffect(false);
  effect.setText("Transform up to one target Werewolf you control");
  this.getSpellAbility().addEffect(effect);
  this.getSpellAbility().addTarget(new TargetCreaturePermanent(0, 1, filter, false));
  // Creatures you control gain trample until end of turn.
  this.getSpellAbility().addEffect(new GainAbilityAllEffect(TrampleAbility.getInstance(), Duration.EndOfTurn, new FilterControlledCreaturePermanent(), "Creatures you control gain trample until end of turn"));
}