From day one, one of the big mysteries of the Marvel Cinematic Universe has been what happened to Nick Fury's eye. Samuel L. Jackson's eye patch-wearing super spy is a staple of the MCU, and while an answer as to what happened to it has been teased, it's never been revealed.
With a young Nick Fury helping Brie Larson's Carol Danvers as she returns to Earth, though, the release of the latest Captain Marvel trailer and some leaked toy images may have provided us with the answer.
In the comics, Fury took shrapnel to his eye in the field during World War II, as detailed in 1966's Sgt. Fury and the Howling Commandos #27, giving him his signature look. However, it's the Ultimate Universe Fury which Jackson's Fury is based on, a version who lost his eye in active duty with Wolverine. While the 616-Fury still has his damaged eye, Ultimate Fury doesn't, which means when we saw Jackson's Fury showing us his heavily-scarred eye in 2014's The Winter Soldier, he really was an amalgamation of the two versions.
Jackson's Fury also left us with an intriguing hint regarding the damage and how the incident influenced his personality thereafter. In a scene with Chris Evans' Captain America, he says, "Last time I trusted someone, I lost an eye." Now, fans went off on their conspiracy theories, with some even positing the someday, once Marvel acquires the X-Men rights, the three claw-like scars across Fury's eye could be retconned to make Wolverine the person who inflicted the marks.
Cut to the present, and as we see Fury cozying up to Carol's cat, Goose (a reference to her being a fighter pilot and a nod towards Top Gun), it appears there's more than meets the eye, no pun intended. In the comics, her cat isn't just a cat. Chewie, as it's known there, is an alien Flerken -- a creature that hides massive tentacles underneath its fuzzy and cuddly exterior. Despite being loyal to Carol, it's quite violent, with its tentacles containing sharp teeth. It's only attacked people in self-defense, as it was responsible for laying and protecting hundreds of eggs to propagate its species.
Of course, Goose ism't being painted as a vicious feline in the trailer, as we see Fury having the time of his life petting the little animal and becoming close friends. But the cat is painted in a sinister light in toy images showcasing Goose muzzled and cuffed like a fugitive, hinting that Fury's trust in the feline might be misplaced, The cat is in manacles and standing on his hind legs, indicating it may be an alien that has to be placed in S.H.I.E.L.D. custody. For what crime? Well, seeing as Fury has developed an affinity for the cat, clearly trusting it, there's a good chance the Flerken attacks Fury and costs him his eye.
Why he'd do such a thing (if he does at all) remains to be seen, of course. But an innocent-looking animal attacking Fury would definitely make sense as to why he developed such a cynical, rough and rugged personality thereafter.
A Flerken assault would certainly teach Fury never to take anything at face value, no matter how peaceful and friendly it may seem to be on the surface. After all, if he does end up being duped and viciously mauled by a cat, it stands to reason major trust issues would ensue, with Fury believing that even the cutest of creatures could be a dangerous villain or weapon of mass destruction in disguise.
Directed by Anna Boden and Ryan Fleck from a script they wrote with Liz Flahive, Carly Mensch, Meg LeFauve, Nicole Perlman, and Geneva Robertson-Dworet, Captain Marvel stars Brie Larson as Carol Danvers, Samuel L. Jackson as Nick Fury, Jude Law as the commander of Starforce, Clark Gregg as Phil Coulson, Lee Pace as Ronan the Accuser, Djimon Hounsou as Korath the Pursuer, Gemma Chan as Minn-Erva, and Ben Mendelsohn, Lashana Lynch, Algenis Perez Soto, McKenna Grace and Annette Bening in as-yet-undisclosed roles. The film arrives on March 8, 2019.