Warning! Spoilers ahead for Invincible season 1’s episode four, called “Neil Armstrong, Eat Your Heart Out.”
Invincible season 1’s fourth episode sent Mark Grayson on a mission to Mars where he encountered alien creatures known as Sequids. Invincible may be the new superhero in town, but he’s already taking on some challenging missions. The latest being a two-week space journey that saw him shadowing the first humans to ever land on Mars. However, shortly after landing on the red planet, Mark crossed paths with Sequids, parasitic cephalopods who had made Mars their home. What are these creatures and how dangerous are they? Here’s everything to know about Invincible’s Sequids and their potential role in the rest of the season.
The space mission was originally planned for Omni-Man — as an excuse to send him off-planet while Cecil investigated his involvement in the murders of the Guardians of the Globe — but Mark volunteered to go in his dad’s place so that he could prove himself. After falling asleep and losing sight of the astronauts, Invincible goes looking for them and winds up battling a group of Sequids, squid-like parasites that connect to a hive mind once attached to a host. While the Martians’ shapeshifting abilities and Invincible’s strength protect them from a cognitive takeover, humans are susceptible to the parasites’ mind control. One of the astronauts left behind becomes host to a Sequid, leading him to attack the Martians with the strength of the hive army.
The Sequids’ origins are unknown. They’re Martian parasites, but they don’t originally hail from the planet. That said, the Sequids are conquerors who seem to want nothing more than to bring chaos and launch a takeover of Earth. They were patiently waiting for the opportunity to do so. The Sequids are similar to the Formic species (aka, Buggers) in Ender’s Game, with their existence on an individual basis not as important as their unity within the hive. In this instance, however, they don’t seem to have a queen responsible for controlling them. Rather, it’s whichever Sequid successfully attaches to a host that is in charge of the others’ actions thereafter. The Sequids can also be compared to the villain Starro from DC Comics, an alien conqueror capable of controlling spores to do its bidding.
The Martians know how dangerous the Sequids are, which is why they wanted to execute the human astronauts, fearful they would be taken over by the squid-like aliens. Of course, the Martians had the opportunity to kill them all, but it seems they aren’t too concerned with the Sequids so long as they aren’t able to attach to a host. Unfortunately, that’s no longer the case. In the comics, the Sequids, now led by the astronaut Rus Livingston, arrive on Earth to launch a global invasion. Mark has to face the consequences of his actions on Mars, which ultimately lead him to take drastic measures to ensure the world's safety.
The Sequids are formidable foes primarily because they’re capable of taking over the minds of humans. With a solid host, the cephalopods can do a lot more damage and it’s possible their arrival on Earth will allow for a bigger scale takeover — there are so many humans to choose from on the planet, after all. Either way, it’s clear Invincible is setting up the Sequids to be one of the series’ primary villains. For now, they (and their host) are still on Mars and don’t pose an immediate threat, but it’s only a matter of time before they show back up to properly begin their conquering.