Thunderbolts* stinger theory: is Doom on the Fantastic Four ship?

Thunderbolts* is a really good movie, and I want to talk about how its post-credit scene ties into Avengers: Doomsday. I have a theory about it, and it's a little out there. The extra-dimensional ship with the Fantastic Four logo on its side might not have the Fantastic Four on board at all. What if it's carrying Robert Downey Jr.'s Doctor Doom?

Thunderbolts* (2025) stars Florence Pugh, Sebastian Stan and David Harbour. At the time I made this case, Fantastic Four: First Steps hadn't come out yet. Everything below was speculation about films that were still to come.

The Thunderbolts* post-credit scene puts the New Avengers at odds with Sam Wilson

In the post-credit scene, the new Avengers are in Avengers Tower. We hear that they're having trouble maintaining their credibility as a new team and being accepted by the public as the Avengers. The reason is that Sam Wilson, Captain America, is fighting them for the trademark to the name. One exchange in the scene points out that he has filed for copyright of the name, and the team complains, "We're losing credibility."

There appear to be clear tensions brewing, not only between Yelena and the team and this new Cap, but even between Bucky and Sam. Those two seemed like best friends, both following Steve Rogers, who went into the past, came back old, and is still up in the air as far as whether he's alive. I would assume he is, because we haven't seen a funeral. And in Brave New World, we saw that Sam and Bucky were still very close.

This tension between Sam and the new team could stem from some of these characters, John Walker specifically, having a troubled past, and from this maybe not being the ideal team of Avengers. I could easily see how that would create a divide between Sam and Bucky, since Bucky doesn't have the cleanest past either.

The "huge space crisis" in Thunderbolts* is likely an incursion

Once the team moves on from the dispute over the name, they talk about a huge space crisis that is happening and that they're being left out of the loop on. As one line puts it: "And now there's this huge space crisis and no one's telling us about it."

This is likely an incursion, a tear in the fabric of space and a collision between realities. We've seen these types of space tears in Spider-Man: No Way Home, Doctor Strange in the Multiverse of Madness and The Marvels. In the Secret Wars comics, incursions are the crisis that sets the stage for Battleworld and the emergence of Doctor Doom.

The extra-dimensional ship in Thunderbolts* carries the Fantastic Four logo

Shortly afterward, we hear that an extra-dimensional ship is entering the atmosphere. It's the same rocket we'd seen in the Fantastic Four: First Steps trailers, and we even get a shot of the Fantastic Four logo on the side of the ship.

The most obvious meaning is that we're seeing the Fantastic Four, who come from a different universe than the mainline MCU, likely entering the mainline MCU after the destruction of their own reality in their movie. Some were speculating that this spoils First Steps by confirming the popular fan theory that the Fantastic Four's universe dies and that they come to the MCU at the end of that film, setting up the events of Doomsday and Secret Wars.

In the trailers for Fantastic Four: First Steps, we've seen Reed's chalkboard featuring multiversal wormholes, portals and bridges between realities, as well as a line about Reed tampering with space and time: "It's my fault. I stretched the bounds of space."

What if Robert Downey Jr.'s Doctor Doom is on that ship instead?

I'm beginning to wonder whether this isn't the Fantastic Four coming into the mainline MCU at all. What if that's not Reed, Sue, Johnny and Ben on board? What if the post-credit scene is a misdirect that makes us think they escape their collapsing universe in their movie, when that's not what happens? What if on board the ship is the man himself, Robert Downey Jr.'s Doctor Doom?

This builds on an earlier theory of mine. In it, Reed and the Fantastic Four fail to save their universe, and with the birth of their newborn son, Franklin, they reluctantly get on a ship and leave before it dies. I suggested that perhaps this would be the catalyst for the creation of RDJ's Doctor Doom, the event that makes him a villain.

Part of that theory was that in realities where Reed Richards, the smartest man alive, doesn't exist, this guy is Tony Stark. In realities where Reed does exist, he's Victor von Doom. Loki was always destined to be a villain so that others could be heroes, even when he didn't want to be one. Perhaps that's the role of the man we know as Tony Stark: where the Fantastic Four exist, he has to play the villain, and in realities without them, like the mainline MCU, he gets to be the hero.

In that original version, Victor, Reed's old rival, joins him in the race against the clock to save their universe. They fail, Reed and the team decide to leave, and they offer to bring Victor with them. Victor refuses to abandon their world, and the whole situation makes him hate Reed even more because he thinks Reed is a coward. Doom stays behind and witnesses the death of his universe. But as in the comics, if Doom is a master of the mystic arts, he could save himself by separating from his body into his astral form. His physical body would die, his soul would be adrift in the barriers of reality, and he could then dreamwalk into or possess the dead body of his variant self, Tony Stark, in the mainline MCU.

The flipped theory: Doctor Doom flees, and maybe takes Franklin with him

Now flip that around. Instead of Doom being the noble one who goes down with the ship while Reed slips out the back door, what if Reed and the Fantastic Four are the ones who refuse to leave and insist on fighting for their world until the bitter end? And what if it's Doom taking the shortcut, cutting the wire, a version of that character who never learned his lessons in that cave and never made that sacrifice in Endgame?

In this version, he's the one saying they need to get out of this universe, that there's no reason to stay and die. He tries to get Reed to think about his newborn son. When that fails, Victor gives up on persuading him, grabs the keys to the rocket and gets out before the universe implodes. Maybe he even takes baby Franklin with him.

That could tie into Doom using Franklin and his reality manipulation powers to conquer the multiverse and rebuild it in his image. Franklin plays a huge part in the 2015 Secret Wars comics, which the MCU is very likely adapting with the whole multiverse of it all. So it could be Doom on board this Fantastic Four ship, making his way to universe 616, and not the Fantastic Four.

As for how the Fantastic Four would survive, there are tons of ways. They could perhaps use Reed's multiversal bridge to escape to another universe in something like an escape pod, once they realize Doom took off with Franklin. Maybe they wind up in the X-Men universe that Monica Rambeau, Deadpool and Wolverine are all in.

A Tony Stark face could give the New Avengers the credibility they want

Imagine how bizarre that would be. This extra-dimensional ship lands on Earth, the New Avengers roll up to see who or what is on board, and out steps a guy they know as Tony Stark, the original Avenger whose former tower they're now living in.

The New Avengers are desperate for validation, credibility and acceptance. What better way to get that than to have Tony Stark from another universe as their team leader? That would definitely seal the deal on who the New Avengers are, at least in the public's eye.

It has long been rumored that, with Doctor Doom sharing Tony Stark's face, he'll take advantage of that fact and form his own team of Avengers loyalists to fight this multiversal war the way he sees fit. Then we'd see another team of Avengers, led by Sam Wilson and accompanied by the X-Men, the Fantastic Four and others, teaming up against Doom.

Doctor Doom could pull the Thunderbolts into destroying another universe

Picture this island of misfit toys, the New Avengers, who have dark pasts, are only now learning to accept themselves, and want to be public-facing heroes. What if RDJ's Doom appeals to them by saying he knows what it's like to be the underdog after all his years living in the shadow of Reed Richards and the Fantastic Four? He also knows what it's like to have a dark side. This well-meaning team, which has felt left out of what's going on in space, could join forces with Doom, who knows all about incursions and was on the brink of solving them. They'd join him in what they think is a fight for the greater good.

This more violent, short-tempered assortment of characters, who are willing to kill, could easily fall on the side of destroying another universe to save their own. That universe would likely be the Fox X-Men universe. Meanwhile, Sam and his Avengers, already at odds with the New Avengers, would be on the side of finding another way out that doesn't involve destroying another reality. Sam's refusal to work with the misfits could be the first wedge that allows for the giant break in Doomsday and Secret Wars.