Some superhero duos save the world; Chris Evans and Sebastian Stan also made friendship look suspiciously good on and off screen. Captain America and Bucky Barnes grew from 1930s Brooklyn best friends into tragic enemies and reunited allies across five films, with The Winter Soldier and Civil War delivering their fiercest fights and most loyal moments. Avengers: Doomsday now brings another reunion, naturally raising questions about what went down.

Evans was happy to discuss what reuniting with Stan was like, but nearly let a spoiler escape before catching himself.

The question at Fan Expo Boston sounded harmless enough: what was Chris Evans’s favorite scene to shoot with Sebastian Stan? Yet asking Captain America about Bucky Barnes has apparently become a dangerous game. Evans began praising their time together, noting how much he loves working with Stan, and the answer quickly wandered toward spoiler territory.

"I was about to start really talking. You almost got me," Evans said, catching himself before his answer could become an Avengers-sized information dump. He then admitted that he very much enjoys working with Sebastian Stan, calling his longtime co-star a "lovely, lovely man." Captain America had escaped the ambush, barely.

Naturally, fans at Fan Expo Boston did not let the near-slip disappear quietly. Evans has previously spoken about how special his scenes with Stan have been, with hindsight making those collaborations feel even more precious. Now, thousands of fan theories are connecting the mysterious hesitation to emotional Steve Rogers and Bucky Barnes material, with some becoming even more convinced that Bucky could face an especially heartbreaking fate.

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Of course, with Captain America’s mysterious return, Bucky back in the mix, and thousands of theories connecting the dots, the speculation shows no signs of slowing down, something evergreen like Evans' opinion on being Team Iron Man.

Marvel fandom has apparently decided that ordinary speculation is terribly passé, so Avengers: Doomsday theories have graduated to full conspiracy couture. The juiciest suggests Steve Rogers and Bucky Barnes will face Victor von Doom together, recreating Civil War with one rather ghastly alteration: their enemy has Tony Stark’s face. Nothing says emotional healing quite like punching your dead friend’s doppelgänger.

Then there is the wonderfully unhinged possibility that Steve Rogers’ Avengers: Endgame retirement caused an incursion, destroying Doom’s universe and earning Captain America a multiversal grudge. Bucky Barnes, meanwhile, gets dragged into whatever fresh cosmic catastrophe has found his best friend. Between revenge, alternate realities, and Civil War echoes, fans have certainly found enough ammunition, and Chris Evans’ near-spoiler has merely poured gasoline onto it.

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What do you think Chris Evans was about to spoil? Let us know in the comments!