Monsters in movies usually go one of two ways: either they're right in the spotlight, kicking and screaming for all the world to see, or, they lurk in the shadows, giving you only the briefest of glimpses of their hideous forms.
And, obviously, it's the latter that really gets your mind racing.
Whether a deliberate tactic to keep you on your toes or just a general disinterest in making themselves known, these monsters will elude you time and time again, never once letting you get a good look at them. In most cases, the sense of mystery they create keeps you guessing about their true nature long after their part in the movie is over.
In other cases, when a movie monster isn't shy about taking centre stage, the shocking abilities they demonstrate make you pretty certain that there's WAY more to them than you ever get to see on-screen. How many other horrifying tricks do they have hidden away up their metaphorical sleeves?
You'll probably never know - and that's part of the fun.
10. Kraken - Pirates Of The Caribbean: Dead Man's Chest (2006)
A big blockbuster movie that takes place primarily out on the ocean wouldn't be complete without a huge prehistoric sea monster, now would it?
The second instalment in the Pirates of the Caribbean series sees Jack Sparrow and co. go up against Davy Jones, the barnacled old captain of The Flying Dutchman. On his travels back and forth from the Locker, Davy Jones somehow managed to get his hands (well, claws) on a Kraken, which he can summon at will like a kind of pet.
The good guys find themselves on the receiving end of this slippery leviathan more than once in Dead Man's Chest, and each time all they get to see of it is a seemingly endless mass of tree-sized tentacles. The bulk of the creature remains underwater, which Will Turner only gets the most superficial two-second look at before he's forced to swim to safety.
And sure, in the next film, At World's End, you do see its corpse slumped on a beach, but even then, it's hardly enough to get a good idea of what it looked like in action.