For a big screen villain, leaving an impression is absolutely everything. Constructing a movie's baddie that is insanely watchable and so striking that we can't help but love to hate them is a seriously tough gig to crack for a screenwriter.
It all comes down to a balancing act essentially: you need to find a way of weaving in a motivation or a drive for a villain's actions in amongst the showcasing of their immense power or intimidating level of skills. Some of the best villains in Hollywood history have also been presented with a slightly grey feel as well, falling somewhere in the murky middle of a traditional moral compass.
Ultimately however, the mystery behind a guy, girl or thing that is keeping their cards especially close to their chest can become the biggest pull going. For us, being unable to work exactly why someone would do some of the sinister things included in this list is the chief reason why these characters have gone down in film history as legends.
10. Ultron - Avengers: Age Of Ultron (2015): 16 Minutes
Ultron has the honour (or dishonour depending on how you want to look at it) of being able to call himself the MCU villain with the lowest amount of screen time.
Portrayed by James Spader for just sixteen minutes in the original theatrical release of the second ever Avengers film, Ultron is an artificial intelligence peace programme designed by Tony Stark and Bruce Banner-gone wrong who spends most of his time on screen either trying to destroy the Avengers or eradicating the human race.
Spader and the surrounding cast do a great job in selling the immense threat carried by Ultron, who literally does not break a sweat throughout the whole film, and there's a real sense of dread whenever the character does appear. Ultron's cold, uncompromising persona and lack of emotions is what truly sells the terror however, leaving a scarring impression on even the ever-chilled figure of Ironman.
Ultron's tale ultimately falls in somewhere between Frankenstein and iRobot, with the AI's unnatural God complex towards humanity making him seem like an outcast and helping to create one of the most memorable villains in MCU history.