Parametric plot of (s*cos(t), s*sin(t), s^(2.5)*sin(2t)/2) where s is in [0,1] and t in R (or, to avoid overlapping, [0,2*pi]).
Looks like a potato chip. We offer you a color option of yellow to boost the feeling of a potato chip.
Also a nice model for a saddle point, since the product is a plot of a curve z=(x^2+y^2)^(1/4)*xy in a neighborbood of (0,0).