We're confident in saying that Marvel's Avengers: Infinity War will be pitting Earth's mightiest heroes against Thanos the Mad Titan, but some casting calls suggest that a secondary villain may be showing up as well. Before we get to just who that might be, let's play a little catch-up to see where we are now.

At the end of Avengers: Age of Ultron, Thor is in search of the Infinity Stones/Gems, some of which have already been accounted for, and all of which can be placed in an incredibly powerful device known as the Infinity Gauntlet. The film's mid-credits stinger shows Josh Brolin's Thanos griping about his incompetent minions and their inability to get the job done, so he grasps the golden gauntlet and affirms to do it himself. So unless Marvel wants to push Thanos further down the road, he should finally make his debut (for more than a few seconds, anyway) in Avengers: Infinity War - Part I.

In an effort to keep the two-part team-up movies from just being an all-out slug fest between the heroes and the mad god, it sounds like another villain will be making his appearance. According to IGN, who first reported the casting news, not only will Adam Warlock be showing up, but his alter ego Magus will appear as well. Their source is the somewhat-suspect site acting-auditions.org, and their casting call is as follows:

Here's the point in the story where we remind you that this casting is a rumor. Thanos is a safe bet, but Adam Warlock and his alter-ego Magus are somewhat longer shots. After the spontaneous generation of Ultron's evil form and the creation of the Vision in Avengers: Age of Ultron, audiences have already been prepped for artificial life traipsing around the Marvel Cinematic Universe. Cue Warlock, otherwise known simply as "Him," an artificially perfect human created by scientists who rebels against his creators. Warlock has had a number of run-ins with the Infinity Gems, Thanos, and the Avengers over his adventures, so it makes sense they they'll all intersect on the big screen. What's less clear is the appearance of Magus - an entity who is inextricably linked to Warlock and manifests in a variety of ways - especially without any planned introduction to Warlock's origin story. (Don't even get me started on the Avengers doppelgangers.)

That being said, there's been a bit of groundwork laid out for Adam Warlock's appearance in the Marvel films. In James Gunn's Guardians of the Galaxy, a large yellow cocoon can be seen in The Collector's gallery, a cocoon which is split open in the film's credits scenes. As the IBT reported last summer, Gunn apparently confirmed that this is Warlock's cocoon during a podcast recorded with Empire, saying the following:

"Well many people may look up to the right of The Collector as we first see him, and you will see a certain duck named Howard that turns to look at the group. That's one of my favourite little things in the background. There are the slither creature from my movie Slither behind The Collector, those guys are pretty obvious. You have Adam Warlock's cocoon, you have all sorts of other characters from Marvel movies."

A few short months later, Cinemablend noticed Gunn was already backpedaling on the cocoon comment:

"Yeah, there’s a cocoon that’s exactly like Adam Warlock’s. I wasn’t really thinking that much when I put that in. That was my idea to put that in there. They’re like, ‘What should we put in?" So I went in the Marvel handbook and like just picked cool things that looked neat to put into the boxes. It looked like Adam’s Warlock cocoon, so now everyone thinks he’s out of there and you know… I don’t know ... There’s a lot of stuff in there and there’s also a lot of things that people think they see that I don’t think is in there – unless the visual effects guys were pulling tricks on me… which they could have!"

So was it really Warlock's cocoon? Will the artificial man be showing up in Avengers: Infinity War in order to battle with/against the Avengers/Thanos/Magus? It's all a bit too early to tell but at least it makes for some fun speculation before the film's May 4, 2018 release date. Until then, feel free to share your thoughts in the comments!