It's really nothing but a language learning website, and no, it will not kidnap your family, or murder you. If it said that, they probably posted that on April Fool's Day.
An app that message you at 3am to train at a langague. Duolingo is also an ugly fucking owl that is annoying as fuck. It getting sad when you dont train at your langague and bullies to Duolingo (which is like everyone) is getting tired of it and deleting the trash app. When you delete it have your email so it keep sending you useless emails like wtf
Duolingo at 3am: Your making me sad, train at your langague
Me: Deleting the app Duolingo: *Continues sending useless mails* i have your email
Duolingo is a very dangerous app. If you download it you will have to learn a language FORVEVER. IF ou miss one day he will come for you and kidnap your family.