Sure, there's King Kong, Godzilla, Cloverfield, and Aliens, but what about monsters that are human-like? Sometimes, those are the most horrifying because we assume they also have our intelligence and ability to plot -
This monster was seriously disturbing. It was the combination of something that should not occur -- eyes should never be in the palms of one's hands! It makes it just distorted and surreal enough to horrify.
This is probably one of my favorites of the human-like monsters. The concept of humans evolving inside of caves with possibly night vision, and slimy pale skin, just disturbs, and the bat-like ears don't help to make me any more comfortable.
30 Days Of Night
Absolutely the best vampires in a movie ever! They were human but distorted and they were not charming or sexy, just pure soul-less feeding machines.
Nightmare On Elm Street
Freddy Krueger was not only like a melting human being, but those gloves with the razor fingers, just horrifying. That he could enter your dreams and slice you up there -- SCARY!!!
What is it with a little being that would scare us? Magic powers? The ability to come and go and mess with our minds? The little sing-song voice? That he's wearing such an adorable costume on such a ghastly creature?
Creature From the Black Lagoon
I have had a mad crush on the Gill Man forever! He was so graceful in the water and so tragically lonely. I had compassion for him and, at the same time, found myself studying the lake cautiously before swimming.
The Wolf Man
Anyone could be a werewolf if they get bitten, right? Full moon - most horrifying time! He's man, but he's animal man, so he is going on instincts and feral, can't be reasoned with, and wants to tear you to ribbons and bite you!
As a kid, Frankenstein scared me the most because he was a cobbled being from parts of dead people. He was revived with electricity. And, he had no soul and no intelligence. Just a big, strong, angry monster with a horrible face. This one was with-the-lights-on-only kind of monster!
The Thing From Another World
This 1951 classic SciFi movie proposed, what if a UFO crashed and an alien was captured in a frozen state? What if that alien thawed out and attacked the remote arctic research station? And, even worse, what if it proved to be a vegetable? This movie took early 1950s theater goers to a new level of horror at the concept of a living form that looks human-like but has powers beyond ours.
Dr. Jekyll and Mr. Hyde
A perfectly normal doctor who upon occasion becomes possessed, goes berserk, and turns into a killing monster. That is the premise of the 1931 film. It's the demons within a normal citizen that are sometimes the most grizzly.
It gets more sinister when a heaven-sent event like birthing a baby becomes something dark and horrifying. A baby monster born from a woman and bent on revenge. This is the premise for this 1974 film.
The Beast Within
This 1982 film was chilling. It opened with a woman raped brutally in the forest and then led into the birth of a child from that cursed act. The baby grows up as a seemingly happy young boy until the hormones of his teens hit and he turns into something dominant and dark.
Michael Myers from "Halloween" fame appeared as a normal boy at the beginning of the story until he killed his sister, and then he just seemed psychotic. But, as the movie advanced, one realized the psychiatrist was afraid of him. Why? Well, once he was loose from the institution, we knew why. We also had to wonder, was it true? Was he the Boogeyman?
These are only some examples of human-monsters in films, but there are a lot of them out there because it's easy to be afraid of a monster, but when you have someone you consider on equal ground showing unusual tendencies, you never quite know who to trust and deep inside you know that they are smart enough to anticipate your moves.