Some movies, horror or otherwise, live and die by their creative creature designs. Whether it's a mega budget blockbuster effort like Guillermo Del Toro's Pacific Rim or a no budget indie like 2005's underrated Isolation, the monster movie cannot hope to succeed unless it impresses with its inventive design.
After all, no one is going to watch An American Werewolf In London so they can get a glimpse of London, or Americans.
However, plenty of famous horrors never reveal their monster, such as The Blair Witch Project, whilst many more are infamous for having embarrassing effects which result in the filmmakers attempting to hide their antagonist in the shadows as long as possible (cough Jaws' rubber shark cough).
With this in mind, it's always a welcome surprise to see a horror which gets by fine without a monster, only to suddenly throw one at the audience. It's all the better when the creature in question is a well-designed, memorable monstrosity, so this list is designed to count the movies which you didn't think had it in them before they floored you with a creative, terrifying, or straight up surreal monster.