A mannequin behind a blue car.
The mannequin is a prop for a horror movie.
The mannequins location can not imply what it is being used for and mannequins can be used for other purposes besides as props, and even if they weren't there is no reason why it has to be for a horror movie necessarily.
exists s1 x1 x2.(a_topic(x1) & behind(x1,x2) & n_car(x2) & a_blue(s1) & Theme(s1,x2) & n_mannequin(x1))
exists p1 x1.(n_mannequin(x1) & exists x2 x3 x4.((x1 = x2) & for(x2,x3) & n_movie(x3) & of(x3,x4) & n_horror(x4) & n_prop(x2)))