Secret Invasion was one of the most explosive Marvel crossovers in the late 2000s, having a major impact throughout the publisher's massive universe. The villainous Skrulls transformed into a bigger threat than ever and their shape-shifting abilities forced Marvel's hero community to wonder who they could trust. And, the fact that their abilities went far beyond merely changing their appearances made things even worse.
The Skrulls in Secret Invasion morphed into familiar heroes in much more intimate ways than simply looking like them. Now, that the storyline is being adapted by the Marvel Cinematic Universe, a similar idea may be employed. Here's how the green-skinned invaders' transformations in the comics were far more than skin-deep.
Secret Invasion's Skrulls are the Most Powerful Iteration of the Species
The Skrulls as a species are similar to DC's Green Martians because they naturally have shape-shifting abilities. Unlike those emerald aliens, however, the Skrulls' powers largely stop here. While they can emulate the appearance of other creatures or objects, they can't necessarily copy their properties. Even in the case of Super-Skrull who has the powers of the Fantastic Four, only gained his powers after going through surgery. Thus, this should mean that the Secret Invasion storyline is impossible, but the Skrulls featured in the series had far more advanced powers.
In this case, they weren't average Skrulls, but rather part of a particularly militant religious sect. They underwent a sort of mystical ritual that not only gave them the appearances of their targets but also convinced them that they were the people they were disguised as. Only the religious phrase "He loves you" could break this charade. This is shown through the Skrull version of Captain America, who believed that he was the real Steve Rogers. These aliens were undetectable by science, psychics and magic. This was all due to the weakening of the Skrull Empire in outer space, making Queen Veranke believe that it was their species' religious destiny to rule Earth.
How the MCU May Adapt the Skrulls
There are going to be several changes in the Disney+ TV adaptation of Secret Invasion. For one, it simply won't be as massive a crossover as the storyline was in the comics, with the Skrulls imitating those with political power instead of actual superheroes. This makes one element of their invasion a lot easier -- impersonating the individuals in question. Since they don't have superpowers or anything of the sort, these humans could easily be abducted, with their memories pulled from them in order for the Skrulls to more accurately portray them. Plus, their lack of powers makes it even easier for the Skrulls to slide under the radar.
One thing that's been questioned by fans, however, is why the Skrulls are suddenly so villainous. In the 2019 film Captain Marvel, they were a more sympathetic and less antagonistic species of aliens. Their transformation into an extremist sect of aliens who are operating in a terroristic manner would be shocking and hard to explain. However, such a take on the Skrulls would match the political thriller elements of Secret Invasion, further exploring their "holy war" and the emulating measures they'll take to fight it.