Starkid's Holy Musical B@man exists in the bdcu (yes. We will be using @tickle-bugs 's creation from now on. It is decided.) And one day Clark catches Bruce singing "fuck you I'm gonna kick your ass" under his breath while he's on his third night of no sleep, halfheartedly tapping away at his computer while nodding off even as he's sitting up. The next time they happen to be in the gym together Clark starts singing it as he's destroying a reenforced punching bag. It takes Bruce a minute, where he makes sure no one else is around, then he joins in. He figures even if Clark tells anyone, no one will believe him.