You've probably heard Katy Perry sing her song Dark Horse before. But you probably never heard Michael Jackson or Frank Sinatra or Metallica or Nirvana give their rendition of that pop song. Don't worry, they never did. But if you close your eyes and listen to this guy sing Katy Perry while doing the impersonations of 20 different musicians and bands, you'll laugh and swear they did. It's fun.
The Boyz II Men version is especially good. Here are the bands and musicians he mimicked: