In the eighties, DC Comics published a Batman comic called The Killing Joke. By Alan Moore and Brian Bolland. You may have heard of it.
Controversial, hated and loved, cherished by some, seen as all that is wrong with comics by others, disowned by its writer and elevated by his fans, there have been essays, books, dissertations about it, and there will be many more to come. Each generation discovers it, interprets it, has it reinterpreted.
But it might have once have been called something else.
There was also a well known post-punk/heavy metal band, Killing Joke, big in the eighties. DC Comics approached the band asking for permission to use the name and a deal was struck. DC could use the name, if the band could use Batman on the covers of their albums, a Neal Adams Batman on the single America and a clip of his cape on the album Outside The Gate.
Oh and one other thing. They got the original artwork to the cover of The Killing Joke comic, and bass player Paul Raven kept it.
Sadly, Raven passed away in 2007. But no one has seen hide nor hair of the original art board since, just this photostat.
Unless… you know different? It would probably sell for a decent six figure sum…