  We have studied the surface geometry and shadows of Schwarzschild black hole
with a halo containing the quadrupolar and octopolar terms. We found the
quadrupole term makes the Schwarzschild black hole prolate for the quadrupole
strength $\mathcal{Q}<0$ and oblate for $\mathcal{Q}>0$, and the octopole term
makes shadow stretch upward for the octopolar strength $\mathcal{O}<0$ and
stretch downward for $\mathcal{O}>0$. The shadow of Schwarzschild black hole
with halo stretches and squeezes along the horizontal direction for
$\mathcal{Q}<0$ and $\mathcal{Q}>0$ respectively. Meanwhile, black hole shadow
shifts upward for $\mathcal{O}<0$ and shifts downward for $\mathcal{O}>0$. We
exhibited the light rays that form the shadow boundary to explain the emergence
of the extraordinary patterns of black hole shadow with the quadrupole and
octopole terms. From the observable width $W$, height $H$, oblateness $K$ and
distortion parameter $\delta_{c}$ of black hole shadow, one can determine the
quadrupole and octopolar strengths of Schwarzschild black hole with halo. Our
results show that the quadrupolar and octopolar terms yield a series of
interesting patterns for the shadow of a Schwarzschild black hole with halo.
