Marvel's Agents of SHIELD is finally giving the MCU a Secret Invasion. In 2007, comic book writer Brian Bendis spearheaded a major Marvel Comics event called "Secret Invasion," which revealed that the shapeshifting Skrulls had been infiltrating human society for years. They'd managed to compromise everything from SHIELD to the Avengers themselves - in fact, the Skrull leader was serving as a member of the Avengers, having substituted herself for Spider-Woman.
When Marvel Studios first announced they were introducing the Skrulls to the MCU in Captain Marvel, astute comic book readers immediately guessed that a Secret Invasion was in the works. But Marvel took a different approach with the Skrulls, revealing them as victims rather than as aggressors, a race who were desperately attempting to survive Kree attempts to wipe them out. It's possible Marvel felt that this direction was simply too predictable, and so decided to switch things up a bit; while Kevin Feige has suggested the arc is still possible, there's no evidence it's imminent.
Step forward Marvel's Agents of SHIELD, which has always enjoyed exploring characters and ideas that the films don't touch upon. Although Agents of SHIELD doesn't feature the Skrulls, it appears to be setting up something of a Secret Invasion story of its own.
Agents of SHIELD's Secret Invasion Plot Explained
Agents of SHIELD season 6 is divided between two plots, one in space and the other on Earth. The Earthbound SHIELD agents are currently dealing with the issue of a Coulson doppelganger called Sarge who either comes from another world, or more likely from another dimension. He's leading a small but dangerous team of agents and he doesn't mind killing anyone in his way. The latest episode, "Code Yellow," finally revealed Sarge's purpose. It seems he's arrived on Earth hunting alien infiltrators - and the creatures he's pursuing are far more sinister than the Skrulls.
These new Agents of SHIELD aliens are bat-like in appearance, clearly highly intelligent, and they possess the ability to take possession of a human host. In order to do this, they literally force themselves down a human's throat, and once inside the body attach themselves to the cardiovascular system. They flood the host with a potent neurotoxin, essentially killing them and turning them into a zombie piloted by the alien. The neurotoxin even serves as an accelerant, a potential self-defense mechanism.
There's no direct comic book parallel for these monstrous beings, but it's possible they're the MCU version of the Brood, a parasitic alien race in the comics. Visually they're very different, but that may simply be because the comic book versions are far too obviously inspired by the Alien movies.
Like Sarge and his team, these aliens appear to tap into the power of leylines in order to travel either between worlds or dimensions. There seem to be quite a significant number of the creatures, given Sarge triggered a detector that appeared to show quite a few temporal anomalies. But it's unclear how long they've been on Earth, or even what they aim to achieve. Disturbingly, SHIELD retrieved one video in which they witnessed the destruction of an entire planet; they believed Sarge to be responsible, but it may actually be an exothermic blast triggered by the aliens on a massive scale.
Secret Invasion Is Perfect For Agents of SHIELD
The truth is that Agents of SHIELD is probably better suited for a Secret Invasion plot than any Marvel movie. This kind of plot is really made for a spy drama rather than a superhero adventure, and frankly for a serialized TV series rather than a movie. Conceptually, it's an idea that works best with a gradual build-up; you start off with the discovery that the aliens exist, and then you tease a sense of paranoia over time by facing every character with a single disturbing question: who do you trust?
That was the initial approach the comics took, with the Avengers learning about the Skrulls when one of the invaders died and reverted to its natural form. However, the main event quickly lost that dark sense of suspicion, turning into a typical superhero slugfest. Fans have largely forgotten that the comic Secret Invasion wasn't well-received back in 2007 and 2008, and its reputation has only recovered because it set up the far more interesting Dark Reign era, in which Norman Osborn used the invasion as a way to portray himself as a hero to the world.
Meanwhile, it does make sense for Agents of SHIELD to avoid the Skrulls. "The movies are the lead dog," Marvel TV's Jeph Loeb recently explained. "Our job is to navigate within that world." As per Captain Marvel, there appear to just be a small number of surviving Skrulls out there in the first place, the race having been brought to the brink of extinction by the Kree, and the few remaining shapeshifters aren't hostile. Feige has suggested that not all Skrulls may be peaceful, but that kind of idea would clearly be reserved for a Captain Marvel sequel. Instead, Agents of SHIELD has launched a fairly similar concept, with a whole different race of aliens.
An Agents of SHIELD Secret Invasion Would Explain Sarge's Role
Assuming this Agents of SHIELD season 6 arc is indeed (very) loosely inspired by Secret Invasion, Sarge may actually be a twisted version of Nick Fury from that story. Fury played a key role in the comics; at the time, he'd gone rogue and was a wanted man. Fury's relationship with Earth's heroes had broken down completely after he'd used a group of A-list heroes like Spider-Man and Wolverine on a mission and then wiped their memories. In fact, Wolverine would have preferred killing Nick Fury to working with him. As a result, when Fury discovered the Skrull invasion, he was forced to recruit a small team and operate from the shadows. He had an adversarial, antagonistic relationship with groups such as the Avengers, right up until the moment the Skrull force stepped out into the open.
It's possible Sarge and his team are the Agents of SHIELD equivalent, albeit with an even more complex backstory. If so, SHIELD may yet find themselves in an unlikely alliance with the Phil Coulson doppelganger, whose methods they disagree with but whose knowledge could prove tremendously valuable.
How Secret Invasion Reshapes Agents of SHIELD Season 6
All this raises two key questions for Agents of SHIELD season 6: what are these alien infiltrators doing on Earth, and have they compromised SHIELD? Right now, the creatures' motives are unknown, but if they are indeed a Brood analog then they may have the simplest of goals; to reproduce, claiming a host and laying eggs within them. Exponential reproduction would ultimately mean every human being on the planet became nothing more than an organic incubator, discarded when they were of no further use. If this is indeed the case, the S.H.I.E.L.D. team is once again facing an extinction level event.
The aliens are clearly very intelligent, meaning it's quite likely they've identified SHIELD as a potential threat. Ironically, the very fact Mack has SHIELD expanding and organized will work against him here, because it will take Dr. Benson time to conduct tests on every SHIELD agent to ensure they aren't already a host. Worse still, it's entirely possible any SHIELD agent could come under an alien's influence right after being tested. Sarge knows how to locate the creatures, though, which means SHIELD may be in desperate need of this alliance - and they'll just have to deal with the pain of working with the man who wears Phil Coulson's face.
Agents of SHIELD continues Fridays on ABC.