Random Most Unspeakable Things The Joker Has Ever Done To Harley Quinn (10 items)

(#10) Joker Turns Harley Into A Constellation

Despite not technically having powers, Joker still attempts some incredibly intricate plots to punish his victims. Tragically, Harley Quinn has been on the receiving end of some of his cruelest schemes. It's terrifying to even think about what the Joker might do to Harley if he had any superpowers.
Well, that's exactly what occurs in the Emperor Joker comic. Joker tricks Mr. Mxyzptlk into transferring over all of his powers, and, mindbogglingly, the first thing the clown decides to do is kill Harley Quinn and turn her into a constellation in the sky.
(#6) Joker Plans To Execute Harley In Front Of Batman

While he may claim to love Harley, readers know that there's no one the Joker truly loves as much as Batman. Seriously, even Bruce Wayne is aware of the Joker's undying love for him.
With this in mind, it doesn't come as much of a shock to find out that, at some point during Grant Morrison's run on Batman, the Joker plans to surprise Batman by killing Harley Quinn right in front of him. The plan horrifies both Batman and Harley, though it's not enough to end the relationship, much to the dismay of comic book fans everywhere.
(#8) Joker Throws Harley Out A Window When She Tries To Help With His Work

The Joker takes pride in his own ability to add a splash of ironic, sadistic humor to all of his schemes, and revels in watching Batman traverse his well-laid plots.
When the Joker decides to feed Batman to a vat full of starving piranhas, Harley tries her best to make that the plan goes off without a hitch. To expedite Batman's death — and to bring to life Joker's plan, titled "The Death of 100 Smiles" — Harley hangs the Dark Knight upside down over a piranha-filled vat.
When Joker finds out that Harley altered one of his plans without his permission, he hits her with a swordfish, jettisoning her out of a window.
(#4) Joker Offers Harley Up As A Volcanic Sacrifice

After years of being at each other's throats, it should come as no surprise that the Joker hatched a secret plan to murder Harley during their wedding ceremony. In Harley Quinn: Futures End, Joker agrees to marry Harley, and the two decide the hold their ceremony atop a fiery volcano on a remote island.
After finishing their vows, it is revealed that The Joker has agreed — behind Harley's back — to let the island's natives sacrifice her in the volcano. So much for their twisted happily ever after.
(#2) Joker Abandons Harley While She Is Pregnant

The comics have never hidden the abusive elements of the Joker's relationship with Harley Quinn. However, the plot rarely takes time to elaborate on Harley's perspective. While it's tempting to focus on the Joker's never-ending run of twisted antics, it's also extremely important to consider how Mr. J.'s actions might make Harley feel, especially when compounded over time.
One of the few glimpses into Harley's damaged psyche comes during an intimate conversation with Black Canary. Here, the reader learns that Harley was at one point pregnant with the Joker's baby, and that he knowingly abandons her for the entirety of her pregnancy. After Harley gave birth to her daughter Lucy, the child was sent to live with Harley's sister.
(#5) Joker Threatens To Cut Harley's Face Off

The Joker's character has seen many variants over the years, most of which revolve around his sheer cruelty. At his most sadistic, the Joker often inflicts some truly horrifying acts of violence upon those he "cares" about.
Due to his constant paranoia regarding Harley's allegiance to him, it's not uncommon for the Joker to force Harley to renew her loyalty through some gruesome or abusive challenge. However, when the Joker says that he's going to have to literally cut Harley's face off, she's understandably a bit hesitant to agree.
To make things (arguably) worse, Joker doesn't even end up going through with the act. Instead, he just throws a hood over Harley's head and walks away, leaving her to cower indefinitely in fear.