From Rocklopedia Fakebandica
Yep. That Batman. But probably not the version you think. This is an animated Batman who performs with a band consisting of Robin, Red Hood, and Nightwing (in other words, three Robins from different periods). They play songs by Dethklok, itself a fake band. The whole thing is produced by Russian animation duo ArhyBES. Not sure how legal it all is, but it's definitely fun to see Batman sing "I'm making time for fighting/I'm clearing time for hitting/We'll meet and I will beat you/Our schedules permitting."