In the 2019 movie, Thanos first appears as a weakened version of his purple self who's quickly beheaded by Thor, and when he returns in Endgame's final act he's overconfident and outmatched by several superheroes. Compare that to Infinity War where Thanos never misses a beat or breaks a sweat and something starts to feel off.
How is Thanos able to so easily acquire all the Infinity Stones and beat the Avengers? The answer might come from an unexpected movie: Groundhog Day.
Like Bill Murray's character in the 1993 comedy classic, Thanos might be repeating the same day over and over until he gets every single moment right. This might sound silly, but it explains a lot. After all, in Infinity War, Thanos is always one step ahead of the Avengers, whether that's outwitting Star-Lord at the Collector's Museum or easily dispatching each enemy he fights in Wakanda.
Could this be because each time he fails to wipe out half of life in the universe he gets another chance to try again?
The closest Thanos comes to failing is on the planet Titan, where he faces an epic team-up of Iron Man, Spider-Man, Dr. Strange, and the Guardians of the Galaxy. But even then, Thanos barely seems phased. Star-Lord's plan falls apart because of information Thanos reveals — something he may have planned after multiple failed attempts. Later, when Iron man draws blood, Thanos seems unconcerned.
Thanos also seems to know who to kill and who can be spared. He murders Loki without hesitation (probably a good idea to get the trickster god out of the way early) and when he reaches the Soul Stone, he kills his adopted daughter Gamora without hesitating. At the same time, he lets Iron Man live on Titan and tosses other heroes like Captain America aside when he could easily kill them with just a bit of extra effort.
Compare the version of Thanos in Infinity War to the one we see in Endgame and the differences are obvious. After completing the Snap, the Mad Titan is weakened but also seems resigned to his fate and willing to die. It's almost as if he no longer has the advantage of seeing every attack before it comes.
And when a younger version of Thanos travels through time at the end of Endgame, he's a lot less imposing than the one we saw in Infinity War. Sure, he's still dangerous and deadly, but he's also a bit of a pushover. Captain America, Scarlet Witch, and Captain Marvel all come pretty close to beating Thanos in one-on-one combat, and he totally fails to realize it when Iron Man steals the Infinity Stones. (That's the kind of thing that Infinity War-era Thanos would have seen coming a mile away.
I can't take complete credit for this Avengers: Endgame theory. The concept that another movie character could be dealing with a Groundhog Day scenario originated in December 2018 on the Fan Theories subreddit, where one person wondered if it could explain the incredible string of luck experienced by Matthew Broderick in Ferris Bueller's Day Off.
"The biggest piece of evidence is how he is able to plan for almost all possible contingencies to make sure his plan works," they wrote.
If you think that sounds like Thanos in Infinity War, you're not wrong. Maybe the Mad Titan just got really lucky, but it almost makes more sense that he has some invisible advantage over the Avengers.
And if Thanos was living out a Groundhog Day scenario it doesn't just explain how he wiped the floor with the Avengers in Infinity War, it also explains how they were able to defeat the most powerful guy in the Marvel Cinematic Universe just one movie later in Avengers: Endgame.
Avengers: Endgame came out one year ago today. Read more: