The rumors are true. Duolingo's iconic mascot, known for his silly antics, has passed on. The language-learning app Duolingo announced on Tuesday that its make-believe mascot, Duo the Owl, mysteriously died and a cause of death has not been determined.

One of the world's most famous cartoon owls got its heavenly wings this week after language-learning platform Duolingo announced the death of its beloved avian mascot. "Authorities are currently investigating his cause of death and we are cooperating fully ...