There's a reason why movie villains so often steal the show.
Whether it's Loki, Darth Vader, Magneto or The Joker, the bad guys don't have to play by the same strict rulebook our heroes usually do, meaning they can be funny, devious, likeable and scary all at the same time, a concoction that usually proves engaging and interesting.
As such, a movie's villain is always one of the most talked-about elements leading up to release, but this hype can be dangerous, especially when it creates expectations which aren't always met. What if that villain barely gets any screen time? What if they just aren't intimidating? Or, what if it turns out an even bigger enemy had been lurking behind the scenes the entire time?
Discovering that who you thought was the lead bad guy is actually second-in-command, a henchman or a pawn in a higher power's game can be quite jarring, and it can either make you appreciate the character even more, or hate what they've become.
Now, these ten villains aren't necessarily poorly portrayed or ineffective, it's just that their position as the main antagonist wasn't as secure as we were all lead to believe.
10. Kaecilius - Doctor Strange
Mads Mikkelsen is great at playing menacing bad guys, so when it was announced that he would be entering the Marvel Cinematic Universe in 2016's Doctor Strange, fans were understandably excited to see what he would do.
Unfortunately, Kaecilius continued that most frustrating of MCU trends: underwhelming villains. It wasn't that Mikkelsen's performance was bad, it was just that the character was written in a very bland way; as an obstacle for Strange to overcome, he was serviceable, but that's really all there was to him.
Kaecilius' impact as a credible bad guy was lessened even further when it was revealed that his plan was to summon Dormammu - an inter-dimensional being with world-destroying levels of power - to Earth, where he would lay waste to the planet.
This resulted in Dormammu actually being the film's main threat, relegating Kaecilius to simply being a herald for a far more powerful, far more destructive villain.
In the end, Kaecilius was bested by Strange thanks to the Time Stone, before being removed from the Earth by Dormammu - and it was the latter who proved a far more difficult test for the soon-to-be Sorcerer Supreme.