Ultron was a turning point for the Avengers in the Marvel Cinematic Universe. Not only did the android's life and death result in the existence of Vision but they also lead to the Sokovia Accords, the Avengers splitting up, and in a sense set the stage for Thanos's arrival on Earth.
But what if Ultron didn't die? That is exactly what one fan theory suggests as well as that the android villain may even have realized Thanos was coming and used this realization to his advantage. The theory, suggested on Reddit by user EmperorJoker, has a few parts to it and a couple of ways Ultron could have survived -- one by jumping into a body or drone unseen in Avengers: Age of Ultron and one in which Ultron is really living on in Vision. You can check out the full theory below.
As you can see, the general thrust of the theory is that, as the poster writes "there are so many ways" that Ultron can be alive. While the idea of Ultron somehow managing to escape into a drone or other body seems a little challenging considering it was Vision who destroyed him using an energy beam from the Mind Stone, the idea of Ultron being part of Vision is an interesting one. It's already acknowledged that Vision is part Ultron -- not only did Ultron and Helen Cho create his body but Vision himself admits he's a mixture of Ultron and JARVIS -- but the idea that Ultron uploaded himself into Vision instead of being destroyed as a way of more or less sitting back and waiting for Thanos to come and destroy most of humanity is kind of chilling. Especially when connected to another theory that Ultron has known all along that Thanos was coming.
Ultron was originally programmed to protect Earth and humanity from extraterrestrial threats. While he uses the internet to learn about his creator and that's what horrifies him into believing the Avengers are the real threat, his sentience is powered by the Mind Stone. It's not impossible that, via the Mind Stone, he learned about Thanos and his plans for the Infinity Stones and the universe as a whole. If Ultron was aware of Thanos and his plans and figured out that he was going to lose to the Avengers, it would be pretty clever of Ultron to hide out in Vision and let Thanos do his work. It would save him some effort, after all, and machines are nothing if not efficient.
All of that said, though, there is a pretty major hole in that aspect of the theory. Even if Ultron survived in Vision, when Thanos took the stone in Infinity War so that he could use its power to wipe out half the life in the universe, Ultron would have died as Vision did. It's also possible that if Ultron had retreated into another body or drone to survive the taking of the Mind Stone or even the snap itself could have destroyed him anyway. After all, exactly what constitutes "life" for the purposes of balancing the universe isn't exactly made clear.
What do you think? Did Ultron somehow survive? Did he hide out inside Vision? Is he inside the Mind Stone? Did Ultron know Thanos was coming? Let us know your thoughts in the comments below.