  Charged rotating black holes of Einstein-Maxwell-Chern-Simons theory in odd
dimensions, $D \ge 5$, may possess a negative horizon mass, while their total
mass is positive. This surprising feature is related to the existence of
counterrotating solutions, where the horizon angular velocity $\Omega$ and the
angular momentum $J$ possess opposite signs. Black holes may further possess
vanishing horizon angular velocity while they have finite angular momentum, or
they may possess finite horizon angular velocity while their angular momentum
vanishes. In D=9 even non-static black holes with $\Omega=J=0$ appear. Charged
rotating black holes with vanishing gyromagnetic ratio exist, and black holes
need no longer be uniquely characterized by their global charges.

High Energy Physics - Theory;General Relativity and Quantum Cosmology