Mostel was one of showbiz’s improbables. Though fat and droopy, he was a magnetic performer, graceful and committed, with a face so expressive, he would have succeeded mute. But mute he was not, and his inimitably inflected voice was just another of his many attributes. He succeeded at comedy first; then drama (most memorably in Ionesco’s “Rhinoceros” in 1961); and finally in musicals. His comic timing and ironically acrobatic physicality made him irresistible in “A Funny Thing Happened on the Way to the Forum” (1962) and, especially, “Fiddler on the Roof” (1964). His movie career, though substantial, was unremarkable — save for his now classic performance as the rapacious Max Bialystock in “The Producers” (1968).