Duo and the Duolingo cast

Duo is Duolingo's green owl and the current champion of menace as brand strategy. He started as a friendly reminder to practice your Spanish and evolved into the internet's favorite passive-aggressive threat, the owl who knows you skipped your lesson and will be waiting. Duolingo leaned all the way in: unhinged TikToks, a costumed Duo at public events doing things no legal team pre-approved, notification copy that reads like a hostage note. The lesson streak became a personality, and the personality became one of the most effective brand characters in tech.