When Monsters Were Real 2015 on netflix

It is said that long, long ago, the wild children were bestowed the gift of eternal youth. But one day, one of them started growing up and according to legend, grew so much he turned into a monster. Ravenous, he ate the smallest children and spread terror in his wake. Forced to seek protection, the village chief decided to banish the children who had become too tall before they had a chance to transform. The forest emu would come get them and escort them to the world of monsters, where they disappeared forever.