I am thinking of that scene that traumatized me in my teens.. was it Ghost Ship?  Where the little girl is in a dance hall on a cruise ship and this rope or something slices though everone but her?
Edit.. Since this blew up a bit, I just watched the clip that someone posted down below.. Fantastic special effects.. Damn.  More brutal than I remembered.  Although now in my adult life I have seen ... not worse, but comparable.