[X-Men: Apocalypse](tag:1194267) isn't even out yet, but showrunner Bryan Singer is thinking about what happens next. Although he's told Empire Magazine that he wants to take a brief break, when they asked who he was interested in using as the next villain he was surprisingly happy to say.
"I'd love to use Proteus somehow... There's a lot visually you could do with a character like that."
Who is Proteus?
Although Proteus isn't a particularly well-known villain like Magneto or Apocalypse, among X-Men fans he's a big deal. In Uncanny X-Men #119, writer Chris Claremont began dropping hints to a powerful, dangerous mutant held prisoner on Muir Isle - the mutant research centre owned by Moira MacTaggert. In the comics, Moira is a scientist, not a government agent.
The threads began to be pulled together in Uncanny X-Men #125, as the shadowy figure of what had once been a man watched Moira and Jean Grey from the shadows. In #126, Moira was forced to make the shocking revelation: this mysterious mutant, who came to be known as Proteus (but who she referred to as Mutant X), was her son.
Proteus' powers are terrifying. On an insane quest for vengeance against his parents, Proteus' psychic form possesses one body after another - burning them out as he goes. He'd have made Wolverine his host, too, if it hadn't been for the adamantium - it turned out Proteus had a weakness for metal.
Claremont upped the ante as he went along, revealing that Proteus could manipulate reality in a terrifyingly psychedelic way. We soon learned that Proteus was even immune to the telepathic power of the Phoenix! This was the kind of villain who Wolverine wound up terrified of, and Cyclops actually had to goad the X-Men back into action!
Ultimately, the X-Men confronted Proteus in Edinburgh, with the mutant's powers fracturing reality. Giving an indication of Proteus' power-levels, the villain almost killed Phoenix. Ultimately, though, it was Colossus who was key to defeating Proteus; shifting into his metal form, Colossus literally beat Proteus until the psychic being shattered.
As a being of pure energy, Proteus can never truly die; but, surprisingly for such a terrifying threat, he's only returned twice - usually as a side-character. The most recent 'return' was in X-Men: Legacy #231-233, where the superb writer Mike Carey had Magneto himself do battle against Proteus. The truth of the matter is that I've always felt Proteus had tremendous potential; I've already written a post for MahMuseComics discussing that!
What could the X-Men film franchise do with such a mutant?
In the movies, Moira MacTaggert is an important character; she was crucial to X-Men: First Class, and returns in X-Men: Apocalypse. That said, Moira's a government agent rather than a scientist, so the character would need subtle reworking.
Wouldn't it be fascinating if the world's governments secretly had a mutant prison, in which they kept the most powerful and dangerous mutants? Imagine the reaction of Charles Xavier if he learned that Moira was involved in something like that?
And imagine the revelation that the dangerous escapee was Moira MacTaggert's son?
This would be a fascinating twist; Proteus' threat would come close to justifying the mutant prison, where mutants were kept because of their power-level rather than their ethics. The X-Men would be placed in a really interesting moral position.
Personally, I think a Proteus movie would be a fascinating twist, and I can't help hoping that Proteus is indeed a future movie villain!