Because the vertex of the parabola (0,0), focus is moved to the left, and x -coordinate is changed. So, it is horizontal parabola that is looking to the left.
It is horizontal parabola, so it has y².
[tex] (y-y_{0})^{2} =4p(x-x_{0})
Coordinates of vertex are x_{0}=0 /and/ y_{0}=0
p=-2
(y-0)^{2} = 4*(-2)(x-0)
\\ \\y^{2}=-8x
[/tex]
