Mr. Gross is the father of the Gross Sisters.
Father Gross acts like a money gambler just like them. One day when he cut in front of Oscar in the road, Oscar later yells at him, making the guy retaliate by smacking his face off like mud. Later, as Oscar came and said that their daughters are starting to get along, he was hoping they could set a good example, and then Gross calmly agrees that they have to do it for the kids. When he accidentally pounded Oscar flat, he apologizes for real and Oscar forgives him.