5. The MCU – Thor Is A Skrull
As the MCU is endlessly growing and adapting, fan theories are relatively few and far between. With so many interconnected narratives planned out so far in advance, it’s hardly the sort of franchise with gaps big enough to insert any plausible theory into, but there is one interesting MCU theory that’s gained a surprising amount of traction online: that Thor is actually a Skrull.
Introduced in Captain Marvel, the Skrull are an alien race capable of shapeshifting – a skill they use to perfectly replicate lifeforms, allowing them to infiltrate planets undetected. This skill is pivotal in the comics’ Secret War storyline, and as the MCU is already adapting that story into a TV series, some fans believe that the foundations for it have already been laid.
The theory posits that MCU mainstay Thor has actually been replaced by a Skrull, and there’s actually a surprisingly good case for how (and when) this happened. As you’d expect from an MCU fan theory, it’s got far too many specific points of “evidence” to detail here, but the general basis of the theory is Thor’s noticeable personality change in Thor: Ragnarok.
In his first four MCU appearances from Thor to Avengers: Age of Ultron, Thor is a relatively serious character, and his drastic personality shift to a more comedic one is the backbone of this interesting theory.