Oh sweet jesus, why are ventriloquist dummies so freakin' scary? Mary Shaw and her wall of dummies was unnerving and I slept with the lights on after I watched this. It's not that it's the scariest thing you'll ever see, it's what your imagination does with it. Plus the look on the victims faces and the end of the film are disturbing.
Honestly, if a ventriloquist dummy ever shows up unannounced on my doorstep, I am not bringing it into my house. I have also emphatically told my friends that they can never buy me a ventriloquist dummy, (which they had considered for comedic effect.)