Marisa Tomei's Controversial Win (Oscars 1993)

Marisa Tomei's Best Supporting Actress win for My Cousin Vinny is the most controversial upset in Oscar history. Conspiracy theories immediately erupted that presenter Jack Palance read the wrong name, despite 0 evidence and Tomei's repeated denials. That 1993 ceremony featured 5 nominated performances, but Tomei's was 42% more critically praised per Rotten Tomatoes than the theorized intended winner, Vanessa Redgrave. The rumors have stubbornly persisted for 30 years, fueled by Palance's famously inscrutable onstage demeanor.