When you think of some of the most successful, popular horror movie villains over the years, they might paint a broad spectrum of types but a lot of them are defined by their terrifying, singular urge to kill. They're often voiceless, sometimes motiveless, always relentless - as if they're designed to be personifications of the threat of death itself. They're a reminder of mortality, ceaseless and unfeeling and they'll get their way.
But there is another breed of villains out there - a more cerebral group whose evil is amplified precisely because of their intellect. They might have a different fear factor to a Michael Myers or Jason Vorhees chasing like morbid superhumans or a supernatural foe you can't reason with, but make no mistake, they're just as dangerous and just as terrifying.
And there's nothing quite as scary as knowing your own personal monster knows EXACTLY what they're doing...
10. Dr Billy Weir - Event Horizon
Sci-fi horror mash-ups are always going to increase the likelihood of intelligent characters, because... well, it's right there in the title: it's the science.
Easily one of the most notorious sci-fi horrors of all time, which is surprisingly divisive considering how viscerally affecting some of the scarier sequences are, also introduces a perversely irresistible monster who starts out as a "normal" smart guy. Event Horizon's Dr William Weir - played wonderfully by Sam Neill - is the designer of the titular ship, a brilliant man of unimaginable scientific prowess.
He's the reason the ship is capable of its incredible feats and also the reason it ends up going to the Hell dimension and becoming sentient (so it's swings and roundabouts), and when it reclaims him as its murderous puppet, he becomes a combination of terrifying animal rage and Weir's existing intelligence. Meaning he's quite the double threat.