1. The problem asks to describe the surface corresponding to the equation $x=0$. 2. The equation $x=0$ represents the plane where the $x$-coordinate is always zero. 3. This plane is the $yz$-plane in the 3D coordinate system. 4. Every point on this plane has coordinates $(0, y, z)$ where $y$ and $z$ can be any real numbers. 5. To sketch this surface, draw the $yz$-plane, which is perpendicular to the $x$-axis and passes through the origin. Final answer: The surface $x=0$ is the $yz$-plane.