It's one of the longest running debates in comic-dom: Will Marvel Studios ever actually make an R-Rated movie as part of the Marvel Cinematic Universe.
Many are skeptical about our chances of ever actually seeing the blood and gore that a decent chunk of Marvel comics's output is full of on the big screen - after all, Marvel is owned by the distinctly family-friendly Disney.
That being said, though, Marvel Studios head honcho Kevin Feige has, in the past, been very open to the idea of an R-Rated Marvel movie, admitting a few years back that they're "definitely open to it."
If we do see an R-Rated Marvel movie, though - and, at this point, we'd be talking about Phase 4 at the earliest - what would it be?
Here are my four leading candidates, in order of likelihood...
4. Moon Knight
Marc Spector - a.k.a. Moon Knight - is a hero who's been in some stage of development at Marvel for years - as Kevin Feige has previously acknowledged:
“Moon Knight’s a challenging, but extremely interesting character. We’ve been discussing various versions of it for years.”
He's also, though, the sort of brutal, post-Batman vigilante who would most readily lend himself to an R-Rated movie adaptation.
Could he, though, be just a little too similar to the Caped Crusader? Spector is, after all, basically just Bruce Wayne - sharing both his wealth and love of dressing up as a costumed, night-dwelling vigilante.
Blade is, in many ways, the easiest sell of any of Marvel's R-Rated heroes. After all, Feige himself has pointed out that "Blade was a great franchise for us." The original Blade made $131 million worldwide, off of a $40 million budget, with the second movie (and even the much-derided third) doing similar business off of limited budgets.
The down side? Pretty much everyone - including a lot of the people who worked on it, it seemed - hated Blade: Trinity. Add to that the fact that Blade naturally exists in a very different part of the Marvel Universe to the costumed heroes we've so far seen in the MCU, and it's...a tough sell.
2. Ghost Rider
Now, when the film rights to Ghost Rider reverted to Marvel back in 2013, a lot of fans were hopeful that we'd finally get the chance to see the iconic, gritty Marvel hero in the MCU.
Those hopes haven't yet been realized - but with a level of name recognition superior to most other heroes in the Marvel stable, could Ghost Rider finding his way to the Marvel on-screen universe just be a matter of time?
1. The Punisher
One of the most popular - among hardcore fans, at least - Marvel heroes of all time, Frank Castle (a.k.a. The Punisher) isn't the easiest character to adapt.
For one thing, he's only loosely what you'd call a hero - as often killing criminals for petty offences as taking on conventional evil-doers - and, on top of that, he has a tendency to kill in pretty...visceral ways.
That being said, though, there's a big fan-base out there for the man in black - and Feige himself has acknowledged that Castle making an appearance in the MCU is very much in the cards.