8 Worst Things Harley Quinn Has Ever Done

4. Killing Gotham's Children

Though kidnapping a family over suspicions that they'd been neglecting their duty of care isn't completely irredeemable, the time Harley straight up murdered Gotham's children definitely is.

Releasing just a month before Harleen would seek pastures new in her own solo series, Detective Comics #23 showcased the mallet-wielding character in the wake of her leaving the Suicide Squad. Compounding this change in surroundings further was the fact that Quinn had recently been relapsing into her former self, a prospect that she was unwilling to entertain.

So, in a bid to ensure that Harleen couldn't reclaim her personality altogether, Quinn embarks on a scheme that should push her over the edge. Handing out explosive video games to Gotham's youngsters, Quinn perches above a rooftop and sends out an update that triggers the explosives within, killing dozens of children - potentially their parents and bystanders too - and not so much as shrugging in response.