With all due respect to Bozo and Pennywise, pop culture’s most popular clown is probably Joker, Batman’s archvillain who started making the Caped Crusader’s life hell back in 1940. That’s when the so-called Clown Prince of Crime first appeared in comic books, quickly becoming the Caped Crusader’s top nemesis — and, along the way, the most iconic of all superhero baddies. When Tim Burton hatched his Batman in 1989, the Joker was the villain. The most acclaimed and commercially successful of Christopher Nolan’s Batman trilogy was The Dark Knight, which featured Heath Ledger’s Oscar-winning performance as the Joker. Jared Leto’s Joker in Suicide Squad was universally loathed — as was the film — but even that movie made bank. And, of course, 2019’s Joker brought in more than a billion dollars worldwide, going on to win Joaquin Phoenix an Oscar. We as a society may be racked with a fear of clowns,...