  We consider the possibility that astrophysical Black Holes (BHs) can violate
the Kerr bound; i.e., they can have angular momentum greater than BH mass, $J >
M$. We discuss implications on the BH apparent shape. Even if the bound is
violated by a small amount, the shadow cast by the BH changes significantly (it
is $\sim$ an order of magnitude smaller) from the case with $J \le M$ and can
be used as a clear observational signature in the search for super--spinning
BHs. We discuss briefly recent observations in the mm range of the
super--massive BH at the Center of the Galaxy, speculating on the possibility
that it might violate the Kerr bound.
