Warning: This article contains spoilers for Uncanny X-Men #18, by Matthew Rosenberg, Carlos Villa, Juan Vlasco, Craig Yeung, Guru-eFx and Joe Caramagna, on sale now.
Mutants have always been the center of the X-Men's world. While the vast majority of Marvel's X-Men and their villains have the X-gene that officially makes the mutants, a handful of non-mutants have still served as members of the team or changed the course of mutant history.
Even though Mister Sinister is one of the X-Men's most fearsome villains, and could reasonably be described as the world's foremost expert on genetic mutation, he's not actually a mutant. Instead, the mad scientist has given himself a wide range of abilities through twisted genetic experiments, the latest of which results in a rather dramatic physical change.
With a seemingly endless army of superpowered clones and the telepathic ability to transfer his consciousness between them, Sinister is the kind of villain who can be temporarily beaten but never truly defeated. As the evil mastermind behind iconic X-Men storylines like "Mutant Massacre" and "Inferno," Mister Sinister poses a threat that's loomed over the X-Men for years.
While fighting the X-Men in Uncanny X-Men #18, Sinister and his clones merge together to form a giant-size Mr. Sinister who towers over the X-Men in a far more literal sense.
After one of the X-Men kills Mr. Sinister's protégés, the Marauders, Mr. Sinister avenges his fallen henchmen by burning down the X-Men's current headquarters at Harry's Hideaway, a bar the X-Men have frequented for years.
In the ensuing fight, Mister Sinister and several of his clones merge together, likely using their shared cellular manipulation abilities, to form a gigantic Mister Sinister. While Sinister has usually had some manner of shape-shifting powers, he's never done anything on this scale or interacted with his clones in this way before.
Although the giant-size Sinister quickly begins to overwhelm the X-Men, he's stopped single-handedly by Havok, who unleashes the full might of his cosmic-fueled plasma powers in one of the most impressive displays of his superhero career. After the blast seemingly burns away his clones, a humbled Mr. Sinister surrenders to the X-Men. In a detail that would fascinate the mad geneticist, Alex Summers was left in a semi-transparent state after defeating Sinister.
Since Sinister made his full debut in Chris Claremont and Marc Silvestri's Uncanny X-Men #221, the villain has been unusually preoccupied with Havok's brother, Cyclops, and his genes as part of his century-long efforts to create the ultimate mutant who could kill his former master, Apocalypse.
Sinister's research on mutation dates back to the 1800s, when he was the twisted human scientist Nathaniel Essex. As his work took him further away from his humanity, he met the ancient Apocalypse and was given immortality and telepathic abilities by the future X-Men villain. However, that partnership grew considerably more tense after Sinister unsuccessfully tried to kill Apocalypse twice in what kicked off Sinister's lifelong efforts to one-up the long-lived mutant villain.
While Sinister has given himself a dozen more abilities through his research, his new ability to grow giant-size could be a reflection of his long-standing desire to kill his former mentor. While Apocalypse's powers have been greatly enhanced by Celestial technology, one of his core mutant powers has always been the ability to change his size and shape, often into giant forms.
Between their common history, shared powers and predilection for sending their minds into clone bodies, Sinister and Apocalypse already have a lot in common. With Sinister's latest ability, he's taken one step closer to making himself the equal to his former mentor.
With a genetic database that included DNA samples from everyone in the world until it was destroyed during Hunt for Wolverine, there's no telling how many other powers or abilities Sinister has given himself by this point. Although he recently took a keen interest in the X-Men's Iceman, he hasn't really launched a large-scale campaign against the X-Men in several years.
Later this summer, Powers of X and House of X will kick off a new era of the X-Men by exploring mutantkind's past. Given his roles throughout the history of the Marvel Universe, Sinister could be set to have a very big impact on the X-Men in the not-too-distant future.