The less widely known but more cooler Hungarian movie: The Fly
This 1980 Hungarian short by Ferenc Rofusz won an Oscar. Hungary was at the time a Communist country and Rofusz himself wasn’t allowed to leave the country to attend the Oscars. Without his knowledge, somebody accepted the award for him during the show. I recall watching an interview once with Rofusz where he explained who the guy was, and how surprised he was during the broadcast to see somebody he didn’t know accepting the award for him. This excerpt from the LA Times in 1981 discusses the mystery person who took his award:
"Academy officials were still wondering late Tuesday night if the real Ferenc Rofusz had accepted his award. Rofusz, the Hungarian producer of the winning animated short film “The Fly,” had not been scheduled to attend the ceremonies. But just as presenters Alan Arkin and Margot Kidder were announcing that the academy would accept on behalf of Rofusz, a bearded man bounded onto the stage, made a short acceptance speech, posed for the obligatory photos..."