1. Captain America Wields Mjolnir
Perhaps Marvel should be blamed for this rumour after showing off footage at Comic-Con of Captain America slightly budging Thor's hammer. Regardless, that early preview was soon followed by reports that the end of the movie would indeed feature Steve Rogers lifting Mjolnir and using it to destroy Ultron. That would have no doubt been a very cool moment. Well, it obviously didn't happen, and The Vision was the one who surprised fans by lifting it. This is a great example of a rumour which originates more from fan speculation that it does any sort of reliable source, and it probably won't surprise you to learn that there are already rumblings of Captain America wielding Mjolnir and finally uttering the iconic "Avengers Assemble!" line in Avengers: Infinity War. Perhaps this time they'll actually be right though.