Avatar: The Last Airbender
When Aang was young, he unknowingly revealed that he was the Avatar when he chose four toys out of thousands, each of which were the childhood toys of the previous Avatars. In Tibetan Buddhism, there is a similar test for reincarnations of a Tulku Lama. In Magic and Mystery in Tibet, Alexandra David-Neel writes that "a number of objects such as rosaries, ritualistic implements, books, tea-cups, etc., are placed together, and the child must pick out those which belonged to the late tulku, thus showing that he recognizes the things which were theirs in their previous life." Each successor is expected to show signs of continuity with the previous Avatar, such as being born within a week of the death.