In 1978, world leaders, starlets and Sweathogs looked on as Superman fought Muhammad Ali in the biggest heavyweight bout in the universe. On December 28, 2016, the gloves come off again -- only to be replaced by bigger, squishier gloves. The alien Scrubb are back, pitting champion against champion for the fate of the planet, and Superman is about to step into the ring with rubber bantamweight, Harley Quinn.

“Harley’s Little Black Book” pairs the homicidal prankster with icons of the DC universe a la “World’s Finest.” Less prestige, more toxic whoopee cushions tooting in stereo. Wonder Woman? Check. Bombshells? Check. With the fifth installment, Supes’ number is up. Writers Amanda Conner and Jimmy Palmiotti just needed to select the right guest artist. It was Dan DiDio who first floated the notion of Neal Adams.

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“My brain instantly went to ‘Superman vs. Muhammad Ali,’” Palmiotti told CBR. “Amanda and I just start laughing. Imagine if we swapped in Harley, how things would go down. And I’m sure there’s nothing Neal would love more than to draw the same exact thing over and over again.”

“Over and over again,” Adams said, laughing warmly. “Well, first I thought, ‘This is sacrilegious.’”

"That’s what we do here!” Conner exclaimed.

“Then I realized -- wait a minute,” Adams said, “It’s Harley! Of course we should do it! It seemed like the silliest thing we could possibly do. On the other hand, when we first did ‘Superman vs. Muhammad Ali’ -- when it was first proposed by Julie Schwartz -- everybody in the office went, ‘That’s stupid! What a ridiculous thing to do!’ This follows in a great tradition!”

Joe Kubert was originally attached to draw “Superman vs. Muhammad Ali,” but was dismissed from the book when the “super-sophisticated boxing establishment” reacted unfavorably toward the legendary artist's “rough, gritty” pencils." Capturing and showcasing likeness was viewed as vital by the powers-that-were, and Adams was known for his relative knack for photorealism. When he was tapped as the new artist, he went to Kubert for his blessing. “He would’ve knocked me out if I hadn’t. But Joe was cool.” Adams insisted on keeping Kubert’s cover layout, tracing it using a lightbox, swapping out the mobsters in the crowd for celebrities. The iconic image begs for close attention, and reprints typically include a key to help identity the famous faces. It’s the comic world’s answer to the “Sgt. Pepper” album cover.

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Neal Adams' self-homage based on Adam Kubert's original cover art for "Superman vs Muhammad Ali"

Fast forward to 2016, and Adams is again paying homage to his late contemporary by employing that same Joe Kubert layout for the cover of “Harley’s Little Black Book” #5. “We have Harley winding up to punch Superman in the puss, all in the same poses from the original cover,” Adams said. “It’s a great tradition of strange dumbness! Why not go for it?”

Naturally, neither book was crafted entirely with Adams’ lightbox. The detailed boxing choreography is the product of the artist’s own intensive study, from reviewing tape of Ali’s fights -- particularly in Manilla -- to his own past experience in the ring. “I don’t box, myself,” Adams said. “Not much. But when I was younger, I did a little boxing, and I’m a ‘mean’ boxer. One of the ways you get mean when you box is to study the other guys. And I did study it.”

This time around, Adams pointed to capturing Harley’s uniquely passionate temperament and up-front fighting style, so removed from Ali’s stoicism, as a particularly engaging contrast. “She’ll bite your head off.”

But how does that stack up against an opponent like Superman? Despite his loss to Ali all those decades ago, this is no mild-mannered slouch. Conner and Palmiotti seem to differ, even with each other, when it comes to the level of respect Harley might have for Superman, though they do agree that she wants to challenge that stature by teasing the Big Blue Boy Scout. Relentlessly. Whether she prioritizes that over the fate of Earth, however, remains to be seen.

“The fun is the ride,” Palmiotti explained. “The trip is the best part of the trip, I think. How would they talk to each other? How do these two treat each other?”

Asked to pretend for a moment they had no creative role in this story, the writers and artist wager the smart money in this clash is on Harley. Adams deems Superman’s chances fairly dismal, what with the over-abundance of red suns out there in the cosmos. For Conner, it’s really a question of Harley’s scrappiness versus Superman’s nobility. Not that righteousness is all that bad, but chivalry and good manners can be a detriment in a brawl with the Suicide Squad’s most unpredictable recruit. So reliant on his powers, does the guy even lift?

As for a bout between Harley and “Mean” Neal Adams in his fighting prime?

“Ohhh. That’s tough,” Conner mused, carefully weighing her options.

“I see Neal sitting at the bar trying to buy her a drink,” Palmiotti decided.

“The soda fountain,” Adams corrected. “I think I’m actually straighter-laced than Superman. More of a boy scout than he is.”

“Harley’s Little Black Book” #5, co-starring Superman, arrives December 28.

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Amanda Conner's variant cover for "Harley's Little Black Book" #5