Interviews and Bloopers on Instagram: "Frank Costanza is one of Seinfeld’s most unforgettable supporting characters, known for his explosive temper, bizarre philosophies, and complete lack of self-awareness. Played by Jerry Stiller, Frank brought constant chaos into every scene, whether he was inventing the holiday Festivus, shouting about the “manssiere,” or clashing endlessly with his son, George. Stiller’s loud, physical performance perfectly contrasted the show’s understated main cast, turni