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?

Sep 9, 2017; Pullman, WA, USA; Boise State Broncos mascot Buster Bronco perform against the Washington State Cougars during the first half at Martin Stadium. / James Snook-Imagn Images In the new ...