This week, we were properly introduced to the Batman Who Laughs, one of the new terrifying villains at the core of DC’s Dark Nights: Metal storyline, bearing a not-exactly subtle resemblance Hellraiser’s Cenobites. Metal is a DC Comics crossover event that combines the wild multiverse weirdness of the company’s classic Crisis events with the horror sensibilities of veteran Batman writer Scott Snyder.

But perhaps even more disturbing than the BWL (Batman Who Laughs) himself are the four pale-skinned, fang-toothed boys dressed as Robin that he keeps around him at all times, leashed on lengths of chain. When the BWL and his Robins made their first appearance in Batman: Metal #2 yesterday, we found out an additional creepy detail: His chained Robins say ‘crow.’ Only ‘crow.’ Over and over again.

Dark Nights: Metal prominently features a team of Justice League-inspired evil Batmans, created from Batman’s deepest insecurities about his own morality. Each represents a time in his career that he could have gone wrong or too far and become villainous himself, and their leader, the Batman Who Laughs, is based on Batman’s fear of the Joker himself. The Robins, it seems are what happens to Robin when Batman becomes more like the Joker than Bruce Wayne.

But why ‘crow?’

While it’s unusually accessible for a big, universe-hopping comics crossover, Batman: Metal is still full of small references for long-time DC Comics readers, like me, to puzzle over. The Robins chanting “crow” was just inexplicable enough to feel like a reference to something — birds and bats are something of a theme in Snyder’s Batman comics, after all. But I couldn’t figure out what, so I mistakenly assumed that it was probably something that would be explained later, to horrifying effect.

But the answer is actually in the next panel, when the Batman Who Laughs calls his Robins to heel with a single word: “Bar.” I just couldn’t figure out why that would be his “cease” command to his Robins.

You see, with four Robins, many fans had assumed that they each represented the four past and present Robins of current DC Continuity. While their uniforms are all the same, they’re still the outfits worn by the first Robin, Dick Grayson. I couldn’t figure out why all four Robins would chant the word ‘crow,’ because I hadn’t put the two words next to each other. Crow and bar become “crowbar.”

Dick Grayson’s uniform was also worn by the Robin who came immediately after him, Jason Todd. And a crowbar is the implement the Joker used to beat Jason Todd to senselessness just before murdering him.

This would also explain why each of the BWL’s four Robins are wearing the same uniform. They don’t represent Dick Grayson, Jason Todd, Tim Drake and Damian Wayne. They only represent Jason Todd, the Robin who was murdered by the Joker in what is perhaps the supervillain’s greatest triumph over Batman in their entire history.