Hibernate Modifying subclass's discriminator value on update

Well, despite the naysayers above I've succeeded in doing the unnatural and have changed the type of a polymorphic Hibernate class.

Dog changeCatToDog(Cat cat){
int res = (Integer) getHibernateTemplate().execute(new HibernateCallback(){
public Object doInHibernate(Session sess) throws Exception {
String hqlUpdate = "update Animal set discriminator = 'dog' where animal_id = :id";
int updatedEntities = sess.createQuery( hqlUpdate )
.setLong( "id", cat.getId() )
return updatedEntities;


return (Dog) getHibernateTemplate().get(Dog.class, cat.getId());