Mario or Uncle Mario (Unknown-1934) was a relative of Sophia Petrillo and Dorothy Zbornak. He was a klutz who accidentally shot himself on the forehead when he accidentally dropped his gun while he was taking out the garbage.
In another story, he was killed in a Block Party, 23 stab wounds and no one saw a thing. Sophia said that everyone hated Mario. She was at his funeral when she left 5 year old Dorothy alone in the hospital to get her tonsils removed, which eventually led into Dorothy's fear of hospitals.