If there's one aspect of movies which endures from our childhood, it's those moments when some terrifying creature sent us scurrying behind the sofa in fear of our lives. Such is the overactive imagination of children combined with the power of cinema that the possibility of these monsters lurching out of the screen to "get" us feels all too real. As we grow up movie monsters don't quite have the same impact, and often when we reflect on the creatures which terrified us as children we feel a little embarrassed to have been so easily frightened, particularly when the special effects have dated terribly in the intervening years. But movie monsters will always retain a special place in the hearts of film fans. For many of us, they were our first introduction to the concept of fear in a fantastical sense (as opposed to more logical fears such as the fear of heights). By the same token, creatively design monsters go some way to triggering our own imaginations - more than a few people who end up working in the entertainment industry as adults did so on account of those childhood moments of dread brought on by latter day monster flicks. There are hundreds of monsters to choose from throughout the course of movie history - this list narrows it down to twenty of the most iconic monster introductions of all time. It's moments like these where a big screen really brings films to life.