Duolingo's beloved mascot Duo has been 'killed' in a tongue-in-cheek marketing ploy, sparking widespread online mourning and tributes from various brands. The language-learning app humorously claimed authorities were investigating Duo’s cause of death, asserting he may have 'died waiting for you to do your lesson.' The announcement featured a playful video depicting Duo's characters carrying his coffin, with responses from celebrities and brands like the World Health Organization and Dua Lipa, who commented on the faux tragedy. This stunt echoes past marketing antics, reminiscent of the 2020 death of Mr. Peanut.