The best part of any horror movie has to be its villain. They're the integral piece that puts the horror in, after all, as what's a scary movie without something to be scared of?
Whether they're special effect creatures or invisible menaces, the one constant is that the level of threat is always telegraphed by characters in the scene reacting to whatever spooky device is bothering them. For the most part, the rest of the set is just background dressing. Or so you'd think.
Sometimes, filmmakers don't want to play by the rules, and just when you think you're watching a movie; it's actually watching you. Monsters are hidden in the background of shots in obvious, unashamed positions, watching and waiting for their time to strike completely unnoticed by anyone else around them.
It's only when your eyes adjust and the creature becomes clear that there's any indication of something being wrong - but by then, it's already too late. And really, it's a reminder that anything could be skulking around our own homes with us blissfully unaware.
Hey, this who exercise makes those Where's Wally books worthwhile, at the very least...