Although the franchise's most recent entries have ventured into more lighthearted fanfare, the early days of DCEU saw the franchise try to go out of its way to be explicitly dark. Even with that in mind, it does feel like there is a chance that Zack Snyder's Justice League might bring the franchise back to its dark roots.
Many of those same dark roots have been influenced by the comics in one way or another. However, as dark as the DCEU has been in the past, there are some moments and stories from the comics that border on being far too darker for the studio to touch for a mainstream, big-screen reimagining.
10 That Time The Joker Beat Batman's Ward To Death ... With Fans' Permission
Jason Todd was not a well-liked Robin. Not only because he had big shoes to fill as Dick Grayson's first predecessor, but he was far more violent than fans had hoped for. And understanding the fan's displeasure, DC took a fan vote to decide Jason's fate. After 10,614 votes were tallied—according to GamesRadar—an extra 72 in favor of his death sealed his fate. DC made fans regret it by having The Joker brutally beat him to death with a crowbar.
His death was alluded to in Batman V Superman as a reason for Batman's more extreme approach to crimefighting, but unless DC wants an R-rated movie one day, they'll steer away from actually showing Jason Todd's demise onscreen.
9 Identity Crisis
A sound argument can be made for Identity Crisis—possibly the darkest storyline in the comics. The DCEU would never dare to get this twisted.
Upon the discovery and ensuing investigation into the death of Sue Dibny, Elongated Man's wife, it is soon revealed that she was assaulted by Dr. Light. To ensure he could never do such a thing again, members of the Justice League have Zatanna use her powers to give Light a lobotomy, wiping his memory and giving him a feeble mind.
8 That Time The Joker Humiliated Barbara And Jim Gordon
Elements of The Killing Joke have been borrowed and place into different DC movies here and there, but the core point where The Joker is torturing Jim Gordon might never see this side of celluloid.
Specifically in regards to the dark imagery of The Joker shooting Barbara Gordon, stripping her naked, and exposing the photos to an equally-exposed Jim Gordon. There are just too many levels of darkness to that sequence that the filmmakers behind the DCEU are too likely to shy away from ever adapting.
7 That Time Speedy Was Addicted To Heroin
They call him Speedy for a reason, but a speedy addiction probably wasn't the reason his creators had in mind originally. "Snowbirds Don't Fly" by Dennis O'Neil and Neal Adams is a two-part storyline depicted in issues #85 and #86 of Green Lantern/Green Arrow.
In a decade where Tony Stark dealt with his own alcoholism and some years ahead of characters like Batman and Captain America experimenting with their own drugs of choice, it was the time that Speedy fought his own addictions while investigating similarly addicted muggers. He eventually gives up his habit, but less out of willpower and more out of pure shame after Green Arrow catches him.
6 That Time Batman Was Addicted To Venom
Yep, that's right, Batman had his own foray into drug addiction once upon a time ago in Batman: Venom, written and penciled by an all-star cast of Dennis O'Neil, Trevor Von Eeden, Russell Braun, and Jose Luis Garcia Lopez.
Long before Venom was notoriously associated with Bane's source of power, it was introduced as Batman's coping mechanism of choice after he failed to save a little girl's life. He experimented with the drug hoping to grow stronger but winds up picking up a habit that's hard to kick instead. The DCEU is no stranger to deconstructing Batman - Ben Affleck's interpretation was a deconstruction of the character itself - but this might be a bit much for mainstream audiences.
5 That Time Speedy Relapsed
Readers can't talk about addiction or even Roy Harper's addictions without talking about how he relapsed after the events of Justice League: Cry for Justice. This story arc written by James Robinson, drawn by Mauro Cascioli was particularly a grim one for a now-adult Harper as not only did he lose his arm, but his kid daughter was violently murdered.
This was followed up with The Rise of Arsenal #3 by J.T. Krul, Geraldo Borges, Kevin Sharpe, and Sergio Arino Peralta, which deserves a special shoutout on account that in it, Harper relapses and while high, he hallucinates a cat for being his dead child.
4 That Time Hal Jordan Killed All Of The Green Lantern
Written by Ron Marz and featuring artwork from Bill Willingham, Fred Haynes, Darryl Banks, the Emerald Twilight storyline offered two key introductions: Kyle Rayner as a new Green Lantern and Hal Jordan as a new villain.
After his home city and its inhabitants are destroyed (already in dark territory here), a desperate Hal Jordan uses the Green Lantern ring to recreate the city right down to the deceased. To make the change permanent, he tracks down all of the Green Lantern Corps members and kills them off for their rings. Even when it was later revealed he was possessed by Parallax the whole time, recontextualizing a beloved hero as a maniacal villain might be too dark even by DCEU standards.
3 That Time Kyle Rayner's Girlfriend Was Stuffed Inside A Refrigerator
In introducing Kyle Rayner as a new Green Lantern, Emerald Twilight also introduced his girlfriend Alexandra DeWitt, but just a few issues later in Green Lantern vol. 3, #54 by Ron Marz, Steve Carr, Derec Aucoin, and Darryl Banks, Rayner finds his girlfriend dead and stuffed in a fridge courtesy of Major Force.
Aside from evoking controversy and coining the "Women in Refrigerators" trope from Gail Simone, anyone who could put themselves in Rayner's shoes have to admit how genuinely dark and horrifying the thought of finding their partner in a fridge like this could be.
2 That Time Joker Skinned A Man Alive
2008 is fondly remembered as the year Heath Ledger's knockout performance in The Dark Knight first graced cinemas around the world, but it was also the year that Brian Azzarello's and Lee Bermejo's Joker first hit shelves as a one-shot graphic novel. Emphasis on the word "graphic" for this one.
Taking a peek into the Joker's criminal life in the underbelly of Gotham, there is a panel where after getting into a disagreement with a club owner, he decides to strip him down of both the owner's clothes and his skin.
1 That Time The Joker Cut His Face-Off And Served The Bat Family Their Own Faces
Clearly, given just how many stories are on this list related to Batman, there are a lot of extremely dark stories starring that character that the DCEU probably won't adapt for the big screen any time soon. Among them is this more recent entry, where. as part of a long-term criminal plan, he has his face sawed off by Dollman and plastered to the wall of Arkham Asylum, just as a warning for what's to come.
What came later was The Joker brainwashing Alfred and kidnapping the Bat-Family before having the butler serve plasters of what appeared to be all of the heroes' faces. That wasn't quite the case, but still, dark.