The Lego Batman Movie
It is a spin-off of the 2014 movie The Lego Movie. It is based on the DC Comics character Batman. It will star Will Arnett as Batman, Ralph Fiennes as Alfred, Michael Cera as Robin, Rosario Dawson as Batgirl, Zach Galifianakis as The Joker, and Mariah Carey as the Mayor of Gotham City.