There's a reason why those Paranormal Activity movies work so well with viewers anxiously seeking scares: The presence of evil is suggested but little is shown, leading viewers to imagine the worst possible horrors and freak themselves out more than any director could. It's a tried and true formula dating back to classic horror flicks like Cat People (1942) and The Haunting (1963). Instead of revealing what the ghosts, demons, or supernatural beasts look like, the directors (Jacques Tourneur and Robert Wise, respectively) use noises and characters' frightened reactions to convey the terror.

When filmmakers reveal their movies' monsters and allow the nightmarish antagonists to linger on screen for long stretches of time, the results can often deflate the tension they've built up. It's impossible to be scared of laughable baddies that suffer from cheap special effects, silly makeup work, or simply lame designs.

Directors and their trusty visual effects collaborators do get it right on occasion. In the new box office champion Sinister, for instance, there's a fictional Pagan deity known as Bughuul whose black-metal-demon look nicely adds to the film's overall creepiness. Sinister has us feeling all kinds of wonderfully nostalgic about the best kinds of scary cinema, but with the presumably implication-heavy Paranormal Activity 4 set to dominate the box office this weekend, it seems that we're heading into another period of less-is-more horror.

And sometimes, especially around Halloween, it feels good to shriek at the sight of something solely conceived to scar brains and linger in thoughts. Hence, the inspiration behind compiling the following list of The 50 Scariest Monsters in Movie History. Here, seeing is believing.

Written by Matt Barone (@MBarone)