Answer
Parabola

Work Step by Step
The vertex, the point where the parabola changes direction, is the origin. We see that the parabola $y = ax^{2} $opens upward if $a>0$ and downward if $a <0$ .
Given: $y = -x^{2} $
Here, $a=-1$
This represents the equation of a parabola which has the standard form as follows:
$y=a(x-h)^{2} +k $
vertex, $(h,k) =(0,0)$
The graph for $y = -x^{2} $ will be a parabola acting downwards.
