5. Loki Planned To Get Caught All Along - The Avengers
An extremely popular fan theory that circulated just after the release of The Avengers suggested that Loki always planned to get caught by the superhero supergroup, and that returning to Asgard with Thor was really just part of his ploy all along. Of course, why Loki would want to return to Asgard is anyone's guess - many have speculated the briefly-sighted Infinity Gauntlet from the first film, perhaps? - but as a lead-in to Thor 2, it's certainly very clever if it turns out to be true this November. However, going by what we've seen so far in trailers, it seems like this one
could be debunked in the coming months, as I suspect that Loki will end up sacrificing himself to save the day in a redemptive manner, given that he has been confirmed not to appear in The Avengers 2. I could be wrong, naturally, and the theory makes a
lot of sense, but if this does turn out to be true, the trailers have concealed it fairly well to date.