Baba Yaga is a crone of East Slavic tradition who lives in a hut that stands and spins on chicken legs and is said to devour people with her iron teeth. Yet in some tales she helps those who pass her tests and shows them the way.
As a threshold-keeper whose good or evil cannot be fixed in advance, she is the embodiment of sealed ambiguity, becoming savior or predator according to how the one who meets her conducts themselves.