Let’s look at the shapeshifting aliens that have plagued Marvel Comics heroes since 1962, and the hints offered by the second trailer.

Since back at 2017’s Marvel Studios panel at San Diego Comic-Con about its first woman-led Marvel Cinematic Universe story, “Captain Marvel,” we’ve known the movie will include some of Marvel Comics’ worst bad guys: a group of dangerous, powerful and ruthless green aliens known as the Skrulls.

We already have an ongoing guide to Carol Danvers’ history, so let’s take a look at the comic book history of this shape-shifting alien race. Nick Fury (a de-aged Samuel L. Jackson) calls out the villainous alien race in the second Captain Marvel trailer — in which our titular hero takes down a Skrull disguised as a sweet old lady — but you might wondering what their deal is as the 21st Marvel Cinematic Universe movie approaches.

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Created by Stan Lee and Jack Kirby, the Skrulls made their auspicious debut way back in 1962’s Fantastic Four #2. These humanoid alien invaders have made a lasting impact on the Marvel Universe, cutting an imposing figure with their pointed elfin ears, ridged jawlines, and beady red eyes. The war-like Skrull Empire has been a constant thorn in the side of everyone from the Fantastic Four to the Avengers and beyond thanks to their powerful shapeshifting abilities and their brutality in combat.

Hundreds of millions of years ago, the Skrull race emerged on the aptly named planet Skrullos in the Andromeda Galaxy. While they were still considered primitives on the evolutionary scale, a group of cosmic engineers known as the Celestials came across the Skrulls and began experimenting on them. Their physiological structure was manipulated so that the Skrull race split into three distinct groups—the Eternals, imbued with long life; the Deviants, capable of shapeshifting; and Normals, or “normies” as I like to call them, who became the ruling class for a long time until the Deviants (with their ability to mimic others and transmogrify themselves) eventually wiped out the other two races to become the last Skrulls standing

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The majority of Skrulls lived far, far away in the totalitarian monarchy’s massive intergalactic empire, which has suffered catastrophic losses over the years due to cosmic menaces like Galactus and the Annihilation Wave. At one point, their empire included a weird star system called the Kral system, which they converted into what was essentially an amusement park for the ultra-rich, complete with recreations of Prohibition-era New York City and a medieval Earth village. They also held intergalactic gladiatorial tournaments, and—wait, isn’t this basically the villain’s plot from Space Jam, but with less basketball?

Several elite Skrull agents have infiltrated the Earth over the years, wreaking havoc and forcing Earth’s superheroes to put aside their differences and stop the Skrulls’ nefarious plans. In one instance, the Skrull Paibok used another Skrull called Lyja to replace Alicia Masters, the Thing’s blind sculptor girlfriend, and had her seduce the Human Torch. Unfortunately for Paibok, Lyja’s love for the Human Torch burned too brightly and she betrayed her people, ultimately sacrificing herself to save Johnny.

First Appearance Fantastic Four

Created by late comic legends Stan Lee and Jack Kirby, the Skrulls first showed up in 1962’s Fantastic Four No. 2. Preparing for an invasion of Earth, they believe the Fantastic Four stand in their way, so four scouts impersonate the hero team and try to turn the public against them.

The Fantastic Four thwarts the effort and the Skrulls scout team ends up transforming into cows. Then Mr. Fantastic/Reed Richards hypnotizes them into believing they’re real cows and leaves them to live out their lives in a field — nullifying the threat in the weirdest way.

Marvel Comics of the ’60s take some gloriously strange turns. (Did anyone drink Skrull-cow milk?!) It’s unlikely they’ll be defeated like that in Captain Marvel… but we can dream.

The Skrulls strike back by sending Kl’rt, better known as Super Skrull, after the team in 1963’s Fantastic Four No. 18. In addition to his regular Skrull abilities, he has all of the Fantastic Four’s powers — Mr. Fantastic’s stretching abilities, Invisible Woman’s manipulation of light waves (aka invisibility), the Thing’s strength and Human Torch’s flame — making him a major threat.

Secret Invasion Plot

This 2008 event, by writer Brian Michael Bendis and artist Leinil Yu, revealed that the Skrulls had infiltrated Earth over a long period by kidnapping and replacing its heroes. Their leader, Queen Veranke, had taken the place of Spider-Woman (who’d been an Avenger for years at that point) ahead of a straight-up invasion by an attack force.

A number of new Super-Skrulls display the powers of various heroes and villains during this conflict. They’re beaten after Mr. Fantastic (who else?) builds a device that can detect the aliens. Veranke is killed and the Skrull population is left greatly diminished.

For a while now, there have been rumors that Secret Invasion will become a part of Captain Marvel and Avengers 4, and perhaps even open/continue/be the center of Phase 4 of the MCU. Those rumors were revived last week when EW published the first details about 2019’s movie: “Before long, Carol finds herself back on Earth with new questions about her past. And she’s got a formidable enemy in the form of the Skrulls — the notorious Marvel baddies made all the more dangerous by their shape-shifting abilities. Ben Mendelsohn plays their leader Talos, who spearheads a Skrull invasion of Earth.”

With the Skrulls popping up in “Captain Marvel” and shapeshifting to infiltrate S.H.I.E.L.D., it seems likely that a story of a secret aliens invasion of Earth could be in the offing. From the sounds of things, Carol Danvers is already superpowered member of the space military team Starforce at the start of the movie, so a Skrull invasion would be a good reason to bring her back home. Samuel L. Jackson’s Nick Fury is in the movie as well, and rooting out Skrulls hidden in S.H.I.E.L.D. sounds a lot like what he’s good at, as seen in “Captain America: Winter Soldier.” ​ (It also makes for a nice callback to the end of “Iron Man,” when Fury told Tony Stark “Think you’re the only superhero​ in the world?”)