Batman Beyond is a great show, and it showcases some evolutions of the characters from the original Bruce Timm series, as well as a darker future. A prevalent villain (created by Batman and Cyborg, unintentionally) in the show is Brother Eye, an all-seeing artificial intelligence. Brother Eye sees human beings as a poison and seeks total control over humanity. To that end, Brother Eye has assimilated many heroes or forced them into hiding. It can meld its technology into organic beings to force them to its will.
Brother Eye created Bat-Joker aka Jokerbot aka Jokerborg as an assassin to eliminate Terry McGinnis, the new Batman in the show. Bat-Joker has a dual personality set and head; the cunning and tactical analysis of Batman, and the viciousness of Joker combined with the order of the Eye.
The figure is a really neat build a figure. The claws that look wing-ish at the back are more poseable than any backpiece I've ever seen, especially at this price point. The figure is tall and imposing, and the dual faces you can switch are pretty neat. There are no accessories in particular if you don't count the wing/claws which are meant to be part, but that doesn't take away from it being a really cool build-a-fig.