Chernabog is a giant evil demon who appears as the only main character in the "Night on Bald Mountain/Ave Maria" segment of the 1940 Disney animated feature film Fantasia. He is usually considered to be the film's overall main villain. As such, he is also a primary member of the Disney Villains franchise.
He is based on the God of the Night in Slavic mythology. At Walpurgis Night (the Witches' Sabbath), he emerges from the peak of Bald Mountain (in reality Mount Triglav in Slovenia) to summon all of his minions, who dance furiously as he throws them into the mountain's fiery pit.
He has been praised as Disney's best representation of pure evil, and as animator Vladimir Tytla's greatest triumph. As a very "raw" representation of evil, he, in his original appearance, is not placed in the context of any real story, and he and his minions' actions are not committed in pursuit of any discernible goal other than general havoc–wreaking and tyranny on all. Some other media has attempted to give his character more concrete context.