Batman sings, if you can call that hoarse growl singing, in a song parody set to the tune of "The Sound of Silence" by Simon and Garfunkel. The song tells an almost-coherent story of the Caped Crusader fighting against crime and villainy in the streets of Gotham City. As usual.
Batman is played by a variety of actors: Ben Affleck, Christian Bale, Adam West, Michael Keaton, and a few others. The villains? There's a whole fleet of them making appearances in this video from How It Should Have Ended.