This is part of what makes the internet great. All you need is an idea and people willing to submit their opinion and you can truly have something great. Epic Rap battles are one of those such things where someone had an idea to act out rap battles of various real and fictional character. Besides the funny raps and funnier costumes the rap battles are chosen by the internet public.
This is personally one of my favorite epic rap battles it features Darth Vader versus Adolf Hitler. This series is truly one of the best of the internet.