If you think about it Projectile Vomiting for Orcs makes sense. They can swallow and reguritate items. Theylike to cause pain and are generally sick puppies. So as well as face biting they could Projectile vomit causing blindness and acid damage. It fits an Orcs mentallity and when they did it a secondary affect would be that what ever they had in their stomaches would be thrown out as well.