Mark Blum (May 14, 1950 - March 26, 2020) was an American actor in movies, on television and stage. He found success with a lead role as Gary Glass in the 1985 film Desperately Seeking Susan, which he followed up the next year with a supporting role as Richard Mason in Crocodile Dundee. He had a regularly recurring role as Union Bob on the Amazon Prime series Mozart in the Jungle from 2014 to 2018.