Like whales and porpoises, bats use echolocation to navigate, bouncing frequencies off nearby objects to orient themselves in the air. Humans can't hear their ultrasonic screeching unless we digitally lower the frequency to something our ears can distinguish. Which is at least partly how we ended up with this: The original 1960s Batman theme, as sung by an artificial chorus of noisy bats. It was arranged by German composer Ulrich Seidel, who assigned each of the keys on his keyboard a different ultrasound sampled from real bats. Yes, it's weird and a little unnerving. But then again, you could say the same thing about Robin's old crime-fighting shorts.