Duolingo says its iconic owl mascot has died unexpectedly. A public relations expert says it’s all part of a clever marketing stunt.

Users of the Duolingo language-learning app will know its owl mascot looks worse and worse the longer a user goes without using the app. But in a first, Duolingo says the owl, dubbed Duo, has now died.

Duo the Owl was known for his silly antics, reminding Duolingo users to complete their daily lessons. He debuted with the app in 2011.

Duo was fatally hit by a Tesla Cybertruck, the language-learning company announced this week. The snarky owl has been the face of Duolingo for over a decade. Why his sudden demise, and what's next?