Answer
Frank Gorshin appeared on "Late Night with Conan O'Brien," a late-night talk show hosted by Conan O'Brien. The show aired on NBC from 1993 to 2009 and featured a mix of comedy sketches, celebrity interviews, and musical performances. Gorshin, known for his portrayal of the Riddler in the Batman television series, made several appearances on the show, showcasing his comedic talents and engaging in witty banter with O'Brien.