You can’t hear the noises bats make — they’re too high-frequency for human ears. But slow them down to audible range, and voila: It turns out they’ve been singing the theme song for the 1960s Adam West Batman series.
OK, so these guys had a little help. Human accomplices changed the pitch of the ultrasonic squeaks so that they could be heard, then plugged them into a “bat organ” — a keyboard where each key corresponds to a different bat noise. Then arranger Ulrich Seidel played the Batman theme on the organ. But we know it’s what the bats were going for all along.