Robert Downey Jr. shares another Avengers: Doomsday behind the scenes picture – and he might be teasing a Galactus showdown

Title: Robert Downey Jr. The BTS Pic for Avengers: Doomsday Is Galactus Finally Coming? The Marvel Cinematic Universe is no stranger to grand spectacles, cryptic teasers, and larger-than-life villains. But when Robert Downey Jr. — the original face of the MCU — posts something even remotely connected to the Avengers, the internet listens. And when that post includes a photo from behind-the-scenes (BTS) of the much-anticipated Avengers: Doomsday, the excitement levels soar. Now, with a single image, fans are speculating that we could be headed straight for a cosmic collision course with one of Marvel's most feared entities: Galactus.

Here’s everything we know (and are guessing) about this latest tease and what it could mean for the future of the MCU.

🌀 The BTS Image That Shook the Multiverse

Earlier this week, Robert Downey Jr. shared an image on his social media that sent Marvel fans into full-on analysis mode. The photo, snapped behind the scenes of what is presumed to be Avengers: Doomsday, shows Downey standing near a green screen setup with what appears to be a galactic backdrop behind him. At first glance, it’s classic MCU production fare — until you look closely.

In the reflection of a metallic prop, eagle-eyed fans believe they spotted a figure that resembles the outline of Galactus’s iconic helmet — the towering, forked headpiece that comic fans have come to associate with the Devourer of Worlds. Zoomed-in versions of the reflection and comparative breakdowns flooded Twitter, Reddit, and TikTok within hours due to the nature of the internet. But the real kicker? Downey’s caption: “The end is never the end… unless he eats it. #AvengersDoomsday.”

What exactly did he mean by “he eats it”? Was it a metaphor? A cryptic wink at Galactus, the planet-devouring giant who looms over Marvel Comics as one of its most formidable cosmic threats? Or is Downey just trolling the fanbase the way only he can?

Either way, it worked. The speculation is running wild.

🌌 Who Is Galactus and Why Would He Matter in Doomsday?

For those unfamiliar with Galactus, he's a character that transcends the typical villain mold. Stan Lee and Jack Kirby first introduced Galactus in 1966. He is a cosmic being that lives off the life energy of entire planets. He is simply evil, not evil in the traditional sense. Galactus represents an unstoppable force of nature, a metaphor for consumption and destruction on a cosmic scale.

In the comics, Galactus often serves as an antagonist for not only the Fantastic Four, but also the Avengers and other Marvel teams. Fans are excited about the idea of him being introduced in a movie literally titled Avengers: Doomsday because his arrival typically signifies the onset of an event of extinction level. If Galactus is indeed part of this movie, it would signify a major shift in the MCU's tone and stakes. After Kang the Conqueror and the multiverse arc, Galactus could be the next "big bad" who isn't tied to timelines, but to survival itself.

🧬 Could Iron Man Return for Real?

The other elephant in the room: why is Robert Downey Jr. even on set?

As fans remember, Tony Stark met his heroic end in Avengers: Endgame after wielding the Infinity Gauntlet to save the universe. His death was emotional, meaningful, and definitive — or at least it seemed that way.

Rumors have swirled for years about how Downey could return. With the multiverse fully unlocked thanks to Loki, Spider-Man: No Way Home, and Doctor Strange in the Multiverse of Madness, the possibility of variants has become a narrative free pass. A Tony Stark from another universe — one who never died, or even one who became a villain — could be the version we’re seeing here.

But what if his appearance is not a resurrection at all?

Some speculate that Downey’s cameo may be more symbolic — perhaps in a hologram, time-travel flashback, or even in AI form à la J.A.R.V.I.S. It would allow him to return without undoing the emotional weight of his Endgame sacrifice. Marvel Studios president Kevin Feige has previously stated they wouldn’t bring Stark back lightly, but if there’s any film that could warrant it, Avengers: Doomsday fits the bill.

💥 Setting the Stage: How Galactus Could Fit Into the MCU

So how does Galactus even fit into this universe, especially considering we haven't seen much cosmic activity post-Endgame beyond the Eternals and Guardians?

That’s precisely where the pieces begin to line up. With the Fantastic Four reboot already in the pipeline and slated for release prior to Avengers: Doomsday, Marvel could easily use that film to tease or introduce Galactus as a looming threat. After all, Galactus is most closely tied to the Fantastic Four lore, and his presence would immediately justify assembling every major hero left in the MCU.

Additionally, the Silver Surfer — Galactus’s herald — has been rumored to appear in future MCU projects. If Surfer arrives first to warn Earth of Galactus’s coming, it could mirror the epic storytelling of the comics, where the Surfer is both a tragic figure and a catalyst for Earth's heroes to unite.

🧠 Fan Theories Take Over

Predictably, Marvel fans have taken to the internet with dozens of theories. Here are some of the most compelling:

Multiversal Collision: With the timelines still unstable, Galactus might exist outside of time, drawn to the energy caused by the incursions mentioned in Doctor Strange 2. He could be the reason the universes are collapsing, making him the perfect endgame-level threat.

Stark’s Legacy vs. Cosmic Force: Perhaps Tony Stark left behind a contingency plan for threats beyond Earth. He might be able to defeat Galactus with the help of his AI, technology, or even old suits. Think of it as Stark’s final gift to the Avengers.

The Rise of the Cosmic Avengers: Fans speculate Avengers: Doomsday could introduce a new lineup of heroes including Captain Marvel, Nova, the Fantastic Four, and possibly mutants, forming a cosmic-level team to fight this galactic menace.

Doom Before Galactus: Some believe Doctor Doom will manipulate the arrival of Galactus to his advantage, possibly setting up a two-tiered villain arc for Doomsday and beyond.

📽️ What This Means for the MCU’s Future

If the rumors are true and Avengers: Doomsday does feature Galactus, the MCU may be moving into its most cosmic and ambitious phase yet. Phase Six or Seven could center on survival against an existential force, rather than just multiversal politics or technological threats.

This also opens the door for characters like the Beyonder, Living Tribunal, or even Eternity — abstract cosmic beings who govern existence. The Marvel Cinematic Universe might finally be ready to embrace the full depth of the comic book source material in ways we’ve only seen hints of.

💬 Final Thoughts

Whether Robert Downey Jr.’s latest post was a calculated teaser or just a nostalgic moment from set, it has undoubtedly stirred the Marvel pot. Galactus is not just another villain — he’s a narrative event, a cataclysmic presence that could redefine the entire cinematic landscape of Marvel.

And if Iron Man truly plays a part in facing him, whether as a variant, AI, or legacy mentor, it could bring full-circle closure to one of the greatest arcs in movie history — and set the stage for a future even more massive than the Infinity Saga.

For now, we’ll just have to keep watching the stars… and Robert Downey Jr.’s Instagram.