Just a few days after news broke that we’d be getting a Martin Scorcese-produced Joker standalone movie, The Hollywood Reporter brings tidings today of yet another Joker spin-off--this one a quote ‘insane and twisted love story’ between the Batman villain and Harley Quinn that will be like ‘When Harry Met Sally on benzedrine.” For the latter, Jared Leto and Margot Robbie will reprise the roles they made (in)famous in last year’s flop, Suicide Squad; the directors of Crazy, Stupid, Love are in final negotiations to direct, because apparently they’re not done exploring love stories that are crazy and stupid.

As GQ’s Joshua Rivera explains, the popularity of the Joker is pretty easy to understand: “He’s a well-loved villain because he’s a cipher, a character that has reinvention is baked into his backstory.” Naturally, this makes him readymade for whatever Hollywood spin-off would have him (which is turning out to be a lot of fucking spin-offs).

But I would venture a guess that there might be another reason for the public’s fascination with this particular Batman villain. Unlike other supervillains, there is no apparent root to the Joker’s evil; it is not an evil that’s easily explained away as the result of, I don’t know, a bad childhood or an old grudge. Part of the reason the Joker was so compelling in Christopher Nolan’s The Dark Knight was that he was seemingly bad just to be bad, an antagonist just for the hell of it, driven almost by an American Psycho-esque ennui. Ultimately, the absence of a clear motive made him perpetually, lingeringly intriguing.

We live in a world today that is interrupted all too frequently by terror attacks that are, if not inexplicable, inconceivable to the common man. It’s human nature to want to know why somebody does horrible things, to explain it away (as the old adage goes, “better the devil you know than the devil you don’t.”) From a character perspective, the inscrutability of the Joker lends itself well to further excavation. But perhaps there lies a more fundamental interest in these films, too: a desire to rationalize, as best we can, ostensibly random acts of terror.