import numpy as np
from mayavi import mlab

x, y, z = np.mgrid[-5:5:150j, -5:5:150j, -2:6:150j]

t=x**2*z+y**2*z-9

mlab.contour3d(t, contours=[0], colormap='YlGnBu') #contours=[0,-10]

mlab.show()